Digital broadcasting system and method of processing data in the digital broadcasting system

ABSTRACT

A transmitting system and a method for processing data are disclosed herein. The transmitting system includes a service multiplexer and at least one transmitter located in a remote position from the service multiplexer. Herein, the service multiplexer generates an RS frame having the size of N(row)xl87(column) bytes including at least one type of mobile service data, packetizes the RS frame into a plurality of mobile service data packets, and multiplexes the packetized mobile service data packets with a main service data packet at a predetermined data rate, thereby transmitting the multiplexed data packets. Herein, each mobile service data packet is configured of a TS header and a data region, and the data region is configured of at least one of a payload region and an adaptation field region. The transmitter recovers the RS frame from the mobile service data packets based upon the TS header of each mobile service data packet transmitted from the service multiplexer, and performs error correction encoding and block encoding on data of the recovered RS frame, thereby transmitting the processed RS frame data to a receiving system.

This application claims the benefit of U.S. Provisional Application No.61/033,432, filed on Mar. 4, 2008, which is hereby incorporated byreference as if fully set forth herein. And this application claims thebenefit of Korean Application No. 10-2009-0015936, filed on Feb. 25,2009, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcasting system fortransmitting and receiving digital broadcast signal, and moreparticularly, to a transmitting system for processing and transmittingdigital broadcast signal, and a receiving system for receiving andprocessing digital broadcast signal and, a method of processing data inthe transmitting system and the receiving system.

2. Discussion of the Related Art

The Vestigial Sideband (VSB) transmission mode, which is adopted as thestandard for digital broadcasting in North America and the Republic ofKorea, is a system using a single carrier method. Therefore, thereceiving performance of the digital broadcast receiving system may bedeteriorated in a poor channel environment. Particularly, sinceresistance to changes in channels and noise is more highly required whenusing portable and/or mobile broadcast receivers, the receivingperformance may be even more deteriorated when transmitting mobileservice data by the VSB transmission mode.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a digital broadcastingsystem and a data processing method that substantially obviate one ormore problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a digital broadcastingsystem and a data processing method that are highly resistant to channelchanges and noise.

Another object of the present invention is to provide a digitalbroadcasting system and a data processing method that can enhance thereceiving performance of the receiving system by performing additionalencoding on mobile service data and by transmitting the processed datato the receiving system.

A further object of the present invention is to provide a digitalbroadcasting system and a data processing method that can also enhancethe receiving performance of the receiving system by inserting knowndata already known in accordance with a pre-agreement between thereceiving system and the transmitting system in a predetermined regionwithin a data region.

A further object of the present invention is to provide a digitalbroadcasting system and a data processing method that can packetize dataof a Reed-Solomon (RS) frame for mobile services from a servicemultiplexer within a transmitting system into a plurality of transportstream (TS) packets, and transmit the packetized TS packets to atransmitter, thereby enabling the transmitting system to maintaincompatibility with the conventional system.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adigital broadcast transmitting system may include a service multiplexerand a transmitter. The service multiplexer may multiplex mobile servicedata and main service data at a predetermined data rate and may transmitthe multiplexed data to the transmitter. The transmitter may performadditional encoding on the mobile service data being transmitted fromthe service multiplexer. The transmitter may also group a plurality ofadditionally encoded mobile service data packets so as to form a datagroup. The transmitter may multiplex mobile service data packetsincluding mobile service data and main service data packets includingmain service data and may transmit the multiplexed data packets to areceiving system.

Herein, the data group may be divided into a plurality of regionsdepending upon a degree of interference of the main service data. Also,a long known data sequence may be periodically inserted in regionswithout interference of the main service data. Also, a receiving systemaccording to an embodiment of the present invention may be used fordemodulating and channel equalizing the known data sequence.

In another aspect of the present invention, a transmitting system mayinclude a service multiplexer and at least one transmitter located in aremote position from the service multiplexer. Herein, the servicemultiplexer generates an RS frame having the size of N(row)×187(column)bytes including at least one type of mobile service data, packetizes theRS frame into a plurality of mobile service data packets, andmultiplexes the packetized mobile service data packets with a mainservice data packet at a predetermined data rate, thereby transmittingthe multiplexed data packets. Herein, each mobile service data packet isconfigured of a TS header and a data region, and the data region isconfigured of at least one of a payload region and an adaptation fieldregion.

The transmitter recovers the RS frame from the mobile service datapackets based upon the TS header of each mobile service data packettransmitted from the service multiplexer, and performs error correctionencoding and block encoding on data of the recovered RS frame, therebytransmitting the processed RS frame data to a receiving system.

Herein, the service multiplexer sets, among the plurality of mobileservice data packets, a payload unit start indicator (PUSI) field valueof the TS header included in the mobile service data packet includingthe first data byte of the RS frame data to ‘1’, and wherein the servicemultiplexer sets the PUSI field value of the TS header included in eachof the remaining mobile service data packets to ‘0’. Also, the servicemultiplexer may set an ensemble identifier corresponding to the RS frameas a packet identifier (PID) of the TS header included in each of theplurality of mobile service data packets.

Herein, the transmitter may extract data included in the payload regionof each mobile service data packet having an ensemble identifiercorresponding to the RS frame, which is to be recovered, as a respectivepacket identifier (PID) value, thereby recovering the RS frame.

In another aspect of the present invention, in a method for processingdata in a transmitting system including a service multiplexer and atleast one transmitter located in a remote position from the servicemultiplexer, the method includes generating a Reed-Solomon (RS) framehaving the size of N(row)×187(column) bytes including at least one typeof mobile service data, packetizing the RS frame into a plurality ofmobile service data packets, wherein each mobile service data packet isconfigured of a TS header and a data region, and wherein the data regionis configured of at least one of a payload region and an adaptationfield region, and multiplexing the packetized mobile service datapackets with a main service data packet at a predetermined data rate,thereby transmitting the multiplexed data packets to each transmitter.

Herein, the method may further include recovering the RS frame from theplurality of mobile service data packets based upon the TS header ofeach mobile service data packet transmitted from the servicemultiplexer, and performing error correction encoding and block encodingon data of the recovered RS frame, thereby transmitting the processed RSframe data to a receiving system.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of a MH frame for transmitting andreceiving mobile service data according to the present invention;

FIG. 2 illustrates an exemplary structure of a VSB frame;

FIG. 3 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspace region;

FIG. 4 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in atime region;

FIG. 5 illustrates an alignment of data after being data interleaved andidentified;

FIG. 6 illustrates an enlarged portion of the data group shown in FIG. 5for a better understanding of the present invention;

FIG. 7 illustrates an alignment of data before being data interleavedand identified;

FIG. 8 illustrates an enlarged portion of the data group shown in FIG. 7for a better understanding of the present invention;

FIG. 9 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames according to the present invention;

FIG. 10 illustrates an example of assigning a single parade to an MHframe according to the present invention;

FIG. 11 illustrates an example of assigning 3 parades to an MH frameaccording to the present invention;

FIG. 12 illustrates an example of expanding the assignment process of 3parades to 5 sub-frames within an MH frame;

FIG. 13 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted;

FIG. 14 illustrates a block diagram showing a general structure of atransmitting system according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating an example of RS frame according tothe present invention;

FIG. 16 is a diagram illustrating a structure of an MH header within anMH service data packet according to the present invention;

FIG. 17( a) and FIG. 17( b) are diagrams illustrating another example ofRS frame according to the present invention; and

FIG. 18 illustrates a block diagram showing an example of a servicemultiplexer of FIG. 14;

FIG. 19 illustrates a structure of a transport stream packet that doesnot include an adaptation field;

FIG. 20 illustrates a structure of a transport stream packet thatincludes an adaptation field;

FIG. 21 is a diagram illustrating an example of packetizing an RS frameinto TS packets according to the present invention;

FIG. 22 is a flowchart illustrating an example of TS-packetizing an RSframe according to the present invention;

FIG. 23 illustrates a block diagram showing an embodiment of atransmitter of FIG. 14;

FIG. 24 illustrates a block diagram showing an example of apre-processor of FIG. 23;

FIG. 25 is a diagram illustrating an example of recovering an RS framefrom mobile service data packets according to the present invention;

FIG. 26 is a flowchart illustrating an example of recovering an RS framefrom mobile service data packets according to the present invention;

FIG. 27 illustrates a conceptual block diagram of the MH frame encoderof FIG. 24;

FIG. 28 illustrates a detailed block diagram of an RS frame encoder ofFIG. 27;

FIG. 29( a) and FIG. 29( b) illustrate a process of one or two RS framebeing divided into several portions, based upon an RS frame mode value,and a process of each portion being assigned to a corresponding regionwithin the respective data group;

FIG. 30( a) to FIG. 30( c) illustrate error correction encoding anderror detection encoding processes according to an embodiment of thepresent invention;

FIG. 31( a) to FIG. 31( d) illustrate an example of performing a rowpermutation (or interleaving) process in super frame units according tothe present invention;

FIG. 32( a) and FIG. 32( b) illustrate an example which a paradeconsists of two RS frames

FIG. 33( a) and FIG. 33( b) illustrate an exemplary process of dividingan RS frame for configuring a data group according to the presentinvention;

FIG. 34 illustrates a block diagram of a block processor according to anembodiment of the present invention;

FIG. 35 illustrates a detailed block diagram of a convolution encoder ofthe block processor;

FIG. 36 illustrates a symbol interleaver of the block processor;

FIG. 37 illustrates a block diagram of a group formatter according to anembodiment of the present invention;

FIG. 38 illustrates a block diagram of a trellis encoder according to anembodiment of the present invention;

FIG. 39 illustrates an example of assigning signaling information areaaccording to an embodiment of the present invention;

FIG. 40 illustrates a detailed block diagram of a signaling encoderaccording to the present invention;

FIG. 41 illustrates an example of a syntax structure of TPC dataaccording to the present invention;

FIG. 42 illustrates an example of a transmission scenario of the TPCdata and the FIC data level according to the present invention;

FIG. 43 illustrates an example of power saving of in a receiver whentransmitting 3 parades to an MH frame level according to the presentinvention;

FIG. 44 illustrates an example of a training sequence at the byte levelaccording to the present invention;

FIG. 45 illustrates an example of a training sequence at the symbolaccording to the present invention;

FIG. 46 illustrates a block diagram of a receiving system according toan embodiment of the present invention;

FIG. 47 is a block diagram showing an example of a demodulating unit inthe receiving system;

FIG. 48 is a block diagram showing an example of an operation controllerof FIG. 47;

FIG. 49 illustrates a block diagram of a block decoder according to anembodiment of the present invention;

FIG. 50( a) and FIG. 50( b) illustrate an exemplary process ofconfiguring one or two RS frame by collecting a plurality of portionsaccording to the present invention; and

FIG. 51 and FIG. 52 illustrate process steps of error correctiondecoding according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. In addition,although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meaning of each term lying within.

Among the terms used in the description of the present invention, mainservice data correspond to data that can be received by a fixedreceiving system and may include audio/video (A/V) data. Morespecifically, the main service data may include A/V data of highdefinition (HD) or standard definition (SD) levels and may also includediverse data types required for data broadcasting. Also, the known datacorrespond to data pre-known in accordance with a pre-arranged agreementbetween the receiving system and the transmitting system.

Additionally, among the terms used in the present invention, “MH”corresponds to the initials of “mobile” and “handheld” and representsthe opposite concept of a fixed-type system. Furthermore, the MH servicedata may include at least one of mobile service data and handheldservice data, and will also be referred to as “mobile service data” forsimplicity. Herein, the mobile service data not only correspond to MHservice data but may also include any type of service data with mobileor portable characteristics. Therefore, the mobile service dataaccording to the present invention are not limited only to the MHservice data.

The above-described mobile service data may correspond to data havinginformation, such as program execution files, stock information, and soon, and may also correspond to A/V data. Most particularly, the mobileservice data may correspond to A/V data having lower resolution andlower data rate as compared to the main service data. For example, if anA/V codec that is used for a conventional main service corresponds to aMPEG-2 codec, a MPEG-4 advanced video coding (AVC) or scalable videocoding (SVC) having better image compression efficiency may be used asthe A/V codec for the mobile service. Furthermore, any type of data maybe transmitted as the mobile service data. For example, transportprotocol expert group (TPEG) data for broadcasting real-timetransportation information may be transmitted as the main service data.

Also, a data service using the mobile service data may include weatherforecast services, traffic information services, stock informationservices, viewer participation quiz programs, real-time polls andsurveys, interactive education broadcast programs, gaming services,services providing information on synopsis, character, background music,and filming sites of soap operas or series, services providinginformation on past match scores and player profiles and achievements,and services providing information on product information and programsclassified by service, medium, time, and theme enabling purchase ordersto be processed. Herein, the present invention is not limited only tothe services mentioned above.

In the present invention, the transmitting system provides backwardcompatibility in the main service data so as to be received by theconventional receiving system. Herein, the main service data and themobile service data are multiplexed to the same physical channel andthen transmitted.

Furthermore, the transmitting system according to the present inventionperforms additional encoding on the mobile service data and inserts thedata already known by the receiving system and transmitting system(e.g., known data), thereby transmitting the processed data.

Therefore, when using the transmitting system according to the presentinvention, the receiving system may receive the mobile service dataduring a mobile state and may also receive the mobile service data withstability despite various distortion and noise occurring within thechannel.

MH Frame Structure

In the embodiment of the present invention, the mobile service data arefirst multiplexed with main service data in MH frame units and, then,modulated in a VSB mode and transmitted to the receiving system.

At this point, one MH frame consists of K1 number of sub-frames, whereinone sub-frame includes K2 number of slots. Also, each slot may beconfigured of K3 number of data packets. In the embodiment of thepresent invention, K1 will be set to 5, K2 will be set to 16, and K3will be set to 156 (i.e., K1=5, K2=16, and K3=156). The values for K1,K2, and K3 presented in this embodiment either correspond to valuesaccording to a preferred embodiment or are merely exemplary. Therefore,the above-mentioned values will not limit the scope of the presentinvention.

FIG. 1 illustrates a structure of a MH frame for transmitting andreceiving mobile service data according to the present invention. In theexample shown in FIG. 1, one MH frame consists of 5 sub-frames, whereineach sub-frame includes 16 slots. In this case, the MH frame accordingto the present invention includes 5 sub-frames and 80 slots. Also, in apacket level, one slot is configured of 156 data packets (i.e.,transport stream packets), and in a symbol level, one slot is configuredof 156 data segments. Herein, the size of one slot corresponds to onehalf (½) of a VSB field. More specifically, since one 207-byte datapacket has the same amount of data as a data segment, a data packetprior to being interleaved may also be used as a data segment.

At this point, two VSB fields are grouped to form a VSB frame.

FIG. 2 illustrates an exemplary structure of a VSB frame, wherein oneVSB frame consists of 2 VSB fields (i.e., an odd field and an evenfield). Herein, each VSB field includes a field synchronization segmentand 312 data segments.

The slot corresponds to a basic time period for multiplexing the mobileservice data and the main service data. Herein, one slot may eitherinclude the mobile service data or be configured only of the mainservice data.

If one MH frame is transmitted during one slot, the first 118 datapackets within the slot correspond to a data group. And, the remaining38 data packets become the main service data packets. In anotherexample, when no data group exists in a slot, the corresponding slot isconfigured of 156 main service data packets.

Meanwhile, when the slots are assigned to a VSB frame, an offset existsfor each assigned position.

FIG. 3 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspace region. And, FIG. 4 illustrates a mapping example of the positionsto which the first 4 slots of a sub-frame are assigned with respect to aVSB frame in a time region.

Referring to FIG. 3 and FIG. 4, a 38^(th) data packet (TS packet #137)of a 1^(st) slot (Slot #0) is mapped to the 1^(st) data packet of an oddVSB field. A 38^(th) data packet (TS packet #137) of a 2^(nd) slot (Slot#1) is mapped to the 157^(th) data packet of an odd VSB field. Also, a38^(th) data packet (TS packet #137) of a 3^(rd) slot (Slot #2) ismapped to the 1^(st) data packet of an even VSB field. And, a 38^(th)data packet (TS packet #137) of a 4^(th) slot (Slot #3) is mapped to the157^(th) data packet of an even VSB field. Similarly, the remaining 12slots within the corresponding sub-frame are mapped in the subsequentVSB frames using the same method.

Meanwhile, one data group may be divided into at least one or morehierarchical regions. And, depending upon the characteristics of eachhierarchical region, the type of mobile service data being inserted ineach region may vary. For example, the data group within each region maybe divided (or categorized) based upon the receiving performance.

In an example given in the present invention, a data group is dividedinto regions A, B, C, and D in a data configuration after datainterleaving.

FIG. 5 illustrates an alignment of data after being data interleaved andidentified. FIG. 6 illustrates an enlarged portion of the data groupshown in FIG. 5 for a better understanding of the present invention.FIG. 7 illustrates an alignment of data before being data interleavedand identified. And, FIG. 8 illustrates an enlarged portion of the datagroup shown in FIG. 7 for a better understanding of the presentinvention. More specifically, a data structure identical to that shownin FIG. 5 is transmitted to a receiving system. In other words, one datapacket is data-interleaved so as to be scattered to a plurality of datasegments, thereby being transmitted to the receiving system. FIG. 5illustrates an example of one data group being scattered to 170 datasegments. At this point, since one 207-byte packet has the same amountof data as one data segment, the packet that is not yet processed withdata-interleaving may be used as the data segment.

FIG. 5 shows an example of dividing a data group prior to beingdata-interleaved into 10 MH blocks (i.e., MH block 1 (B1) to MH block 10(B10)). In this example, each MH block has the length of 16 segments.Referring to FIG. 5, only the RS parity data are allocated to portionsof the first 5 segments of the MH block 1 (B1) and the last 5 segmentsof the MH block 10 (B10). The RS parity data are excluded in regions Ato D of the data group. More specifically, when it is assumed that onedata group is divided into regions A, B, C, and D, each MH block may beincluded in any one of region A to region D depending upon thecharacteristic of each MH block within the data group.

Herein, the data group is divided into a plurality of regions to be usedfor different purposes. More specifically, a region of the main servicedata having no interference or a very low interference level may beconsidered to have a more resistant (or stronger) receiving performanceas compared to regions having higher interference levels. Additionally,when using a system inserting and transmitting known data in the datagroup, wherein the known data are known based upon an agreement betweenthe transmitting system and the receiving system, and when consecutivelylong known data are to be periodically inserted in the mobile servicedata, the known data having a predetermined length may be periodicallyinserted in the region having no interference from the main service data(i.e., a region wherein the main service data are not mixed). However,due to interference from the main service data, it is difficult toperiodically insert known data and also to insert consecutively longknown data to a region having interference from the main service data.

Referring to FIG. 5, MH block 4 (B4) to MH block 7 (B7) correspond toregions without interference of the main service data. MH block 4 (B4)to MH block 7 (B7) within the data group shown in FIG. 5 correspond to aregion where no interference from the main service data occurs. In thisexample, a long known data sequence is inserted at both the beginningand end of each MH block. In the description of the present invention,the region including MH block 4 (B4) to MH block 7 (B7) will be referredto as “region A (=B4+B5+B6+B7)”. As described above, when the data groupincludes region A having a long known data sequence inserted at both thebeginning and end of each MH block, the receiving system is capable ofperforming equalization by using the channel information that can beobtained from the known data. Therefore, the strongest equalizingperformance may be yielded (or obtained) from one of region A to regionD.

In the example of the data group shown in FIG. 5, MH block 3 (B3) and MHblock 8 (B8) correspond to a region having little interference from themain service data. Herein, a long known data sequence is inserted inonly one side of each MH block B3 and B8. More specifically, due to theinterference from the main service data, a long known data sequence isinserted at the end of MH block 3 (B3), and another long known datasequence is inserted at the beginning of MH block 8 (B8). In the presentinvention, the region including MH block 3 (B3) and MH block 8 (B8) willbe referred to as “region B(=B3+B8)”. As described above, when the datagroup includes region B having a long known data sequence inserted atonly one side (beginning or end) of each MH block, the receiving systemis capable of performing equalization by using the channel informationthat can be obtained from the known data. Therefore, a strongerequalizing performance as compared to region C/D may be yielded (orobtained).

Referring to FIG. 5, MH block 2 (B2) and MH block 9 (B9) correspond to aregion having more interference from the main service data as comparedto region B. A long known data sequence cannot be inserted in any sideof MH block 2 (B2) and MH block 9 (B9). Herein, the region including MHblock 2 (B2) and MH block 9 (B9) will be referred to as “regionC(=B2+B9)”. Finally, in the example shown in FIG. 5, MH block 1 (B1) andMH block 10 (B10) correspond to a region having more interference fromthe main service data as compared to region C. Similarly, a long knowndata sequence cannot be inserted in any side of MH block 1 (B1) and MHblock 10 (B10).

Herein, the region including MH block 1 (B1) and MH block 10 (B10) willbe referred to as “region D (=B1+B10)”. Since region C/D is spacedfurther apart from the known data sequence, when the channel environmentundergoes frequent and abrupt changes, the receiving performance ofregion C/D may be deteriorated.

FIG. 7 illustrates a data structure prior to data interleaving. Morespecifically, FIG. 7 illustrates an example of 118 data packets beingallocated to a data group. FIG. 7 shows an example of a data groupconsisting of 118 data packets, wherein, based upon a reference packet(e.g., a 1^(st) packet (or data segment) or 157^(th) packet (or datasegment) after a field synchronization signal), when allocating datapackets to a VSB frame, 37 packets are included before the referencepacket and 81 packets (including the reference packet) are includedafterwards.

In other words, with reference to FIG. 5, a field synchronization signalis placed (or assigned) between MH block 2 (B2) and MH block 3 (B3).Accordingly, this indicates that the slot has an off-set of 37 datapackets with respect to the corresponding VSB field.

The size of the data groups, number of hierarchical regions within thedata group, the size of each region, the number of MH blocks included ineach region, the size of each MH block, and so on described above aremerely exemplary. Therefore, the present invention will not be limitedto the examples described above.

FIG. 9 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames, wherein the 5 sub-frames configure anMH frame. For example, the method of assigning data groups may beidentically applied to all MH frames or differently applied to each MHframe. Furthermore, the method of assigning data groups may beidentically applied to all sub-frames or differently applied to eachsub-frame. At this point, when it is assumed that the data groups areassigned using the same method in all sub-frames of the corresponding MHframe, the total number of data groups being assigned to an MH frame isequal to a multiple of ‘5’.

According to the embodiment of the present invention, a plurality ofconsecutive data groups is assigned to be spaced as far apart from oneanother as possible within the MH frame. Thus, the system can be capableof responding promptly and effectively to any burst error that may occurwithin a sub-frame.

For example, when it is assumed that 3 data groups are assigned to asub-frame, the data groups are assigned to a 1^(st) slot (Slot #0), a5^(th) slot (Slot #4), and a 9^(th) slot (Slot #8) in the sub-frame,respectively. FIG. 9 illustrates an example of assigning 16 data groupsin one sub-frame using the above-described pattern (or rule). In otherwords, each data group is serially assigned to 16 slots corresponding tothe following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14, 3, 11, 7,and 15. Equation 1 below shows the above-described rule (or pattern) forassigning data groups in a sub-frame.

$\begin{matrix}{{j = {( {{4i} + 0} )\mspace{14mu} {mod}\; 16}}{{Herein},\mspace{14mu} \begin{matrix}{{0 = {{0\mspace{14mu} {if}\mspace{14mu} i} < 4}},} \\{{0 = {{2\mspace{14mu} {else}\mspace{14mu} {if}\mspace{14mu} i} < 8}},} \\{{0 = {{1\mspace{14mu} {else}\mspace{14mu} {if}\mspace{14mu} i} < 12}},} \\{0 = {3\mspace{14mu} {{else}.}}}\end{matrix}}} & {{Equation}\mspace{20mu} 1}\end{matrix}$

Herein, j indicates the slot number within a sub-frame. The value of jmay range from 0 to 15 (i.e., 0≦j≦15). Also, value of i indicates thedata group number. The value of i may range from 0 to 15 (i.e., 0≦i≦15).

In the present invention, a collection of data groups included in a MHframe will be referred to as a “parade”. Based upon the RS frame mode,the parade transmits data of at least one specific RS frame.

The mobile service data within one RS frame may be assigned either toall of regions A/B/C/D within the corresponding data group, or to atleast one of regions A/B/C/D. In the embodiment of the presentinvention, the mobile service data within one RS frame may be assignedeither to all of regions A/B/C/D, or to at least one of regions A/B andregions C/D. If the mobile service data are assigned to the latter case(i.e., one of regions A/B and regions C/D), the RS frame being assignedto regions A/B and the RS frame being assigned to regions C/D within thecorresponding data group are different from one another.

In the description of the present invention, the RS frame being assignedto regions A/B within the corresponding data group will be referred toas a “primary RS frame”, and the RS frame being assigned to regions C/Dwithin the corresponding data group will be referred to as a “secondaryRS frame”, for simplicity. Also, the primary RS frame and the secondaryRS frame form (or configure) one parade. More specifically, when themobile service data within one RS frame are assigned either to all ofregions A/B/C/D within the corresponding data group, one paradetransmits one RS frame. In this case, also the RS frame will be referredto as a “primary RS frame”. Conversely, when the mobile service datawithin one RS frame are assigned either to at least one of regions A/Band regions C/D, one parade may transmit up to 2 RS frames.

More specifically, the RS frame mode indicates whether a paradetransmits one RS frame, or whether the parade transmits two RS frames.Table 1 below shows an example of the RS frame mode.

TABLE 1 RS frame mode (2 bits) Description 00 There is only one primaryRS frame for all group regions 01 There are two separate RS frames.Primary RS frame for group regions A and B Secondary RS frame for groupregions C and D 10 Reserved 11 Reserved

Table 1 illustrates an example of allocating 2 bits in order to indicatethe RS frame mode. For example, referring to Table 1, when the RS framemode value is equal to ‘00’, this indicates that one parade transmitsone RS frame. And, when the RS frame mode value is equal to ‘01’, thisindicates that one parade transmits two RS frames, i.e., the primary RSframe and the secondary RS frame. More specifically, when the RS framemode value is equal to ‘01’, data of the primary RS frame for regionsA/B are assigned and transmitted to regions A/B of the correspondingdata group. Similarly, data of the secondary RS frame for regions C/Dare assigned and transmitted to regions C/D of the corresponding datagroup.

As described in the assignment of data groups, the parades are alsoassigned to be spaced as far apart from one another as possible withinthe sub-frame. Thus, the system can be capable of responding promptlyand effectively to any burst error that may occur within a sub-frame.

Furthermore, the method of assigning parades may be identically appliedto all sub-frames or differently applied to each sub-frame. According tothe embodiment of the present invention, the parades may be assigneddifferently for each MH frame and identically for all sub-frames withinan MH frame. More specifically, the MH frame structure may vary by MHframe units. Thus, an ensemble rate may be adjusted on a more frequentand flexible basis.

FIG. 10 illustrates an example of multiple data groups of a singleparade being assigned (or allocated) to an MH frame. More specifically,FIG. 10 illustrates an example of a plurality of data groups included ina single parade, wherein the number of data groups included in asub-frame is equal to ‘3’, being allocated to an MH frame. Referring toFIG. 10, 3 data groups are sequentially assigned to a sub-frame at acycle period of 4 slots. Accordingly, when this process is equallyperformed in the 5 sub-frames included in the corresponding MH frame, 15data groups are assigned to a single MH frame. Herein, the 15 datagroups correspond to data groups included in a parade. Therefore, sinceone sub-frame is configured of 4 VSB frame, and since 3 data groups areincluded in a sub-frame, the data group of the corresponding parade isnot assigned to one of the 4 VSB frames within a sub-frame.

For example, when it is assumed that one parade transmits one RS frame,and that a RS frame encoder located in a later block performsRS-encoding on the corresponding RS frame, thereby adding 24 bytes ofparity data to the corresponding RS frame and transmitting the processedRS frame, the parity data occupy approximately 11.37% (=24/(187+24)×100)of the total code word length. Meanwhile, when one sub-frame includes 3data groups, and when the data groups included in the parade areassigned, as shown in FIG. 10, a total of 15 data groups form an RSframe. Accordingly, even when an error occurs in an entire data groupdue to a burst noise within a channel, the percentile is merely 6.67%(=1/15×100). Therefore, the receiving system may correct all errors byperforming an erasure RS decoding process. More specifically, when theerasure RS decoding is performed, a number of channel errorscorresponding to the number of RS parity bytes may be corrected. Bydoing so, the receiving system may correct the error of at least onedata group within one parade. Thus, the minimum burst noise lengthcorrectable by a RS frame is over 1 VSB frame.

Meanwhile, when data groups of a parade are assigned as described above,either main service data may be assigned between each data group, ordata groups corresponding to different parades may be assigned betweeneach data group. More specifically, data groups corresponding tomultiple parades may be assigned to one MH frame.

Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, data groups includedin other parades that are to be assigned to an MH frame are alsorespectively assigned according to a cycle period of 4 slots.

At this point, data groups of a different parade may be sequentiallyassigned to the respective slots in a circular method. Herein, the datagroups are assigned to slots starting from the ones to which data groupsof the previous parade have not yet been assigned.

For example, when it is assumed that data groups corresponding to aparade are assigned as shown in FIG. 10, data groups corresponding tothe next parade may be assigned to a sub-frame starting either from the12^(th) slot of a sub-frame. However, this is merely exemplary. Inanother example, the data groups of the next parade may also besequentially assigned to a different slot within a sub-frame at a cycleperiod of 4 slots starting from the 3^(rd) slot.

FIG. 11 illustrates an example of transmitting 3 parades (Parade #0,Parade #1, and Parade #2) to an MH frame. More specifically, FIG. 11illustrates an example of transmitting parades included in one of 5sub-frames, wherein the 5 sub-frames configure one MH frame.

When the 1^(st) parade (Parade #0) includes 3 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘0’ to ‘2’ for i in Equation 1. Morespecifically, the data groups of the 1^(st) parade (Parade #0) aresequentially assigned to the 1^(st), 5^(th), and 9^(th) slots (Slot #0,Slot #4, and Slot #8) within the sub-frame. Also, when the 2^(nd) paradeincludes 2 data groups for each sub-frame, the positions of each datagroups within the sub-frames may be obtained by substituting values ‘3’and ‘4’ for i in Equation 1.

More specifically, the data groups of the 2^(nd) parade (Parade #1) aresequentially assigned to the 2^(nd) and 12^(th) slots (Slot #3 and Slot#11) within the sub-frame.

Finally, when the 3^(rd) parade includes 2 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘5’ and ‘6’ for i in Equation 1. Morespecifically, the data groups of the 3^(rd) parade (Parade #2) aresequentially assigned to the 7^(th) and 11^(th) slots (Slot #6 and Slot#10) within the sub-frame.

As described above, data groups of multiple parades may be assigned to asingle MH frame, and, in each sub-frame, the data groups are seriallyallocated to a group space having 4 slots from left to right. Therefore,a number of groups of one parade per sub-frame (NOG) may correspond toany one integer from ‘1’ to ‘8’. Herein, since one MH frame includes 5sub-frames, the total number of data groups within a parade that can beallocated to an MH frame may correspond to any one multiple of ‘5’ranging from ‘5’ to ‘40’.

FIG. 12 illustrates an example of expanding the assignment process of 3parades, shown in FIG. 11, to 5 sub-frames within an MH frame.

FIG. 13 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted.

As described above, an MH frame is divided into 5 sub-frames. Datagroups corresponding to a plurality of parades co-exist in eachsub-frame. Herein, the data groups corresponding to each parade aregrouped by MH frame units, thereby configuring a single parade.

The data structure shown in FIG. 13 includes 3 parades, one ESGdedicated channel (EDC) parade (i.e., parade with NoG=1), and 2 serviceparades (i.e., parade with NoG=4 and parade with NoG=3). Also, apredetermined portion of each data group (i.e., 37 bytes/data group) isused for delivering (or sending) FIC information associated with mobileservice data, wherein the FIC information is separately encoded from theRS-encoding process. The FIC region assigned to each data group consistsof one FIC segments.

Meanwhile, the concept of an MH ensemble is applied in the embodiment ofthe present invention, thereby defining a collection (or group) ofservices. Each MH ensemble carries the same QoS and is coded with thesame FEC code. Also, each MH ensemble has the same unique identifier(i.e., ensemble ID) and corresponds to consecutive RS frames.

As shown in FIG. 13, the FIC segment corresponding to each data groupdescribed service information of an MH ensemble to which thecorresponding data group belongs.

Furthermore, FIG. 13 illustrates a structure further including aseparate EDC parade apart from the service parade and wherein electronicservice guide (ESG) data are transmitted in the 1St slot of eachsub-frame.

FIG. 14 illustrates a block diagram showing a general structure of adigital broadcast transmitting system according to an embodiment of thepresent invention.

Herein, the digital broadcast transmitting includes a servicemultiplexer 100 and a transmitter 200. Herein, the service multiplexer100 is located in the studio of each broadcast station, and thetransmitter 200 is located in a site placed at a predetermined distancefrom the studio. The transmitter 200 may be located in a plurality ofdifferent locations. Also, for example, the plurality of transmittersmay share the same frequency. And, in this case, the plurality oftransmitters receives the same signal. This corresponds to datatransmission using Single Frequency Network (SFN). Accordingly, in thereceiving system, a channel equalizer may compensate signal distortion,which is caused by a reflected wave, so as to recover the originalsignal. In another example, the plurality of transmitters may havedifferent frequencies with respect to the same channel. This correspondsto data transmission using Multi Frequency Network (MFN).

A variety of methods may be used for data communication each of thetransmitters, which are located in remote positions, and the servicemultiplexer. For example, an interface standard such as a synchronousserial interface for transport of MPEG-2 data (SMPTE-310M). In theSMPTE-310M interface standard, a constant data rate is decided as anoutput data rate of the service multiplexer. For example, in case of the8VSB mode, the output data rate is 19.39 Mbps, and, in case of the 16VSBmode, the output data rate is 38.78 Mbps. Furthermore, in theconventional 8VSB mode transmitting system, a transport stream (TS)packet having a data rate of approximately 19.39 Mbps may be transmittedthrough a single physical channel. Also, in the transmitting systemaccording to the present invention provided with backward compatibilitywith the conventional transmitting system, additional encoding isperformed on the mobile service data. Thereafter, the additionallyencoded mobile service data are multiplexed with the main service datato a TS packet form, which is then transmitted. At this point, the datarate of the multiplexed TS packet is approximately 19.39 Mbps.

At this point, the service multiplexer 100 receives at least one type ofmain service data and table information (e.g., PSI/PSIP table data) foreach main service and encapsulates the received data into a transportstream (TS) packet.

Also, the service multiplexer 100 generates an RS frame included atleast one type of mobile service data, thereby encapsulating thegenerated RS frame into a plurality of transport stream (TS) packets.

The RS frame generated from the service multiplexer 100 may furtherinclude table information for the corresponding mobile service.

And, the service multiplexer 100 multiplexes the encapsulated TS packetsfor main service and the encapsulated TS packets for mobile servicebased upon a predetermined multiplexing rule, thereby outputting themultiplexed TS packets to the transmitter 200.

At this point, the RS frame generated from the service multiplexer 100has the size of N (row)×187 (column), as shown in FIG. 15. Herein, Nrepresents the length of a row (i.e., number of columns), and187corresponds to the length of a column (i.e., number of rows.

In the present invention, each row configured of N bytes will bereferred to as an MH service data packet for simplicity. The MH servicedata packet may be configured of a 2-byte MH header and a (N−2)-byte MHpayload. Herein, the assigning 2 bytes to the MH header region is merelyexemplary. The above-described configuration may be altered by thesystem designer and will, therefore, not be limited only to the examplepresented in the description of the present invention.

The RS frame is generated by collecting (or gathering) table informationand/or mobiles service data collectively corresponding to a size of(N−2)(row)×187 (column) bytes. According to an embodiment of the presentinvention, the mobile service data has the form of an IP datagram.Herein, the RS frame may include table information and IP datagramcorresponding to at least one mobile service. For example, IP datagramand table information of two different types of mobile service data,such as news service (e.g., IP datagram for mobile service 1) and stockinformation service (e.g., IP datagram for mobile service 2), may beincluded in a single RS frame.

More specifically, either table information of a section structure or anIP datagram of a mobile service data may be assigned to an MH payloadwithin an MH service data packet configuring the RS frame.Alternatively, either an IP datagram of table information or an IPdatagram of a mobile service data may be assigned to an MH payloadwithin an MH service data packet configuring the RS frame.

At this point, the size of the MH service data packet including the MHheader may not be equal to N bytes.

In this case, stuffing bytes may be assigned to the surplus (orremaining) payload region within the corresponding MH service datapacket. For example, after assigning program table information to an MHservice data packet, when the length of the corresponding MH servicedata packet including the MH header is equal to (N−20) bytes, stuffingbytes may be assigned to the remaining 20-byte region.

The RS frame may be assigned to at least one of regions A/B/C/D within adata group by the transmitter. In the description of the presentinvention, when the RS frame is assigned to regions A/B/C/D within thedata group, or when the RS frame is assigned to regions A/B, the RSframe will be referred to as a primary RS frame. Alternatively, when theRS frame is assigned to regions C/D, the RS frame will be referred to asa secondary RS frame.

FIG. 16 is a diagram illustrating examples of fields allocated to the MHheader region within the MH service data packet according to the presentinvention. Examples of the fields include type_indicator field,error_indicator field, stuff_indicator field, and pointer field.

The type_indicator field can allocate 3 bits, for example, andrepresents a type of data allocated to payload within the correspondingMH service data packet. In other words, the type_indicator fieldindicates whether data of the payload is IP datagram or program tableinformation. At this time, each data type constitutes one logicalchannel. In the logical channel which transmits the IP datagram, severalmobile services are multiplexed and then transmitted. Each mobileservice undergoes demultiplexing in the IP layer.

The error_indicator field can allocate 1 bit, for example, andrepresents whether the corresponding MH service data packet has anerror. For example, if the error_indicator field has a value of 0, itmeans that there is no error in the corresponding MH service datapacket. If the error_indicator field has a value of 1, it means thatthere may be an error in the corresponding MH service data packet.

The stuff_indicator field can allocate 1 bit, for example, andrepresents whether stuffing byte exists in payload of the correspondingMH service data packet. For example, if the stuff_indicator field has avalue of 0, it means that there is no stuffing byte in the correspondingMH service data packet. If the stuff_indicator field has a value of 1,it means that stuffing byte exists in the corresponding MH service datapacket.

The pointer field can allocate 11 bits, for example, and representsposition information where new data (i.e., new signaling information ornew IP datagram) starts in the corresponding MH service data packet.

For example, if IP datagram for mobile service 1 and IP datagram formobile service 2 are allocated to the first MH service data packetwithin the RS frame as illustrated in FIG. 15, the pointer field valuerepresents the start position of the IP datagram for mobile service 2within the MH service data packet.

Also, if there is no new data in the corresponding MH service datapacket, the corresponding field value is expressed as a maximum valueexemplarily. According to the embodiment of the present invention, since11 bits are allocated to the pointer field, if 2047 is expressed as thepointer field value, it means that there is no new data in the packet.The point where the pointer field value is 0 can be varied depending onthe type_indicator field value and the stuff_indicator field value.

It is to be understood that the order, the position, and the meaning ofthe fields allocated to the header within the MH service data packetillustrated in FIG. 16 are exemplarily illustrated for understanding ofthe present invention. Since the order, the position and the meaning ofthe fields allocated to the header within the MH service data packet andthe number of additionally allocated fields can easily be modified bythose skilled in the art, the present invention will not be limited tothe above example.

FIG. 17( a) and FIG. 17( b) illustrate another examples of RS frameaccording to the present invention. FIG. 17(a) illustrates an example ofprimary RS frame to be allocated to regions A/B within the data group,and FIG. 17(b) illustrates an example of secondary RS frame to beallocated to regions C/D within the data group.

In FIG. 17( a) and FIG. 17( b), a column length (i.e., the number ofrows) of the RS frame to be allocated to the regions A/B and a columnlength (i.e., the number of rows) of the RS frame to be allocated to theregions C/D are 187 equally. However, row lengths (i.e, the number ofcolumns) may be different from each other.

According to the embodiment of the present invention, when the rowlength of the primary RS frame to be allocated to the regions A/B withinthe data group is N1 bytes and the row length of the secondary RS frameto be allocated to the regions C/D within the data group is N2 bytes, acondition of N1>N2 is satisfied. In this case, N1 and N2 can be varieddepending on the transmission parameter or a region of the data group,to which the corresponding RS frame will be transmitted.

For convenience of the description, each row of the N1 and N2 bytes willbe referred to as the MH service data packet. The MH service data packetwithin the RS frame to be allocated to the regions A/B within the datagroup can be comprised of MH header of 2 bytes and payload of N1-2bytes. Also, the MH service data packet within the RS frame to beallocated to the regions C/D within the data group can be comprised ofMH header of 2 bytes and payload of N2-2 bytes.

In the present invention, the primary RS frame for the regions A/Bwithin the data group and the secondary RS frame for the regions C/Dwithin the data group can include at least one of program tableinformation and IP datagram. Also, one RS frame can include IP datagramcorresponding to one or more mobile services.

Corresponding parts of FIG. 15 can be applied to the other parts, whichare not described in FIG. 17( a) and FIG. 17( b).

Meanwhile, the value of N, which corresponds to the number of columnswithin an RS frame, can be decided according to Equation 2.

$\begin{matrix}{N = {\lfloor \frac{5 \times {NoG} \times {PL}}{187 + P} \rfloor - 2}} & {{Equation}\mspace{20mu} 2}\end{matrix}$

Herein, NoG indicates the number of data groups assigned to a sub-frame.PL represents the number of SCCC payload data bytes assigned to a datagroup. And, P signifies the number of RS parity data bytes added to eachcolumn of the RS frame. Finally, └x┘ is the greatest integer that isequal to or smaller than X.

More specifically, in Equation 2, PL corresponds to the length of an RSframe portion. The value of PL is equivalent to the number of SCCCpayload data bytes that are assigned to the corresponding data group.Herein, the value of PL may vary depending upon the RS frame mode, SCCCblock mode, and SCCC outer code mode. Table 2 to Table 5 belowrespectively show examples of PL values, which vary in accordance withthe RS frame mode, SCCC block mode, and SCCC outer code mode. The SCCCblock mode and the SCCC outer code mode will be described in detail in alater process.

TABLE 2 SCCC outer code mode for for for for Region A Region B Region CRegion D PL 00 00 00 00 9624 00 00 00 01 9372 00 00 01 00 8886 00 00 0101 8634 00 01 00 00 8403 00 01 00 01 8151 00 01 01 00 7665 00 01 01 017413 01 00 00 00 7023 01 00 00 01 6771 01 00 01 00 6285 01 00 01 01 603301 01 00 00 5802 01 01 00 01 5550 01 01 01 00 5064 01 01 01 01 4812Others Reserved

Table 2 shows an example of the PL values for each data group within anRS frame, wherein each PL value varies depending upon the SCCC outercode mode, when the RS frame mode value is equal to ‘00’, and when theSCCC block mode value is equal to ‘00’. For example, when it is assumedthat each SCCC outer code mode value of regions A/B/C/D within the datagroup is equal to ‘00’ (i.e., the block processor 302 of a later blockperforms encoding at a coding rate of ½), the PL value within each datagroup of the corresponding RS frame may be equal to 9624 bytes. Morespecifically, 9624 bytes of mobile service data within one RS frame maybe assigned to regions A/B/C/D of the corresponding data group.

TABLE 3 SCCC outer code mode PL 00 9624 01 4812 Others Reserved

Table 3 shows an example of the PL values for each data group within anRS frame, wherein each PL value varies depending upon the SCCC outercode mode, when the RS frame mode value is equal to ‘00’, and when theSCCC block mode value is equal to ‘01’.

TABLE 4 SCCC outer code mode for Region A for Region B PL 00 00 7644 0001 6423 01 00 5043 01 01 3822 Others Reserved

Table 4 shows an example of the PL values for each data group within aprimary RS frame, wherein each PL value varies depending upon the SCCCouter code mode, when the RS frame mode value is equal to ‘01’, and whenthe SCCC block mode value is equal to ‘00’. For example, when each SCCCouter code mode value of regions A/B is equal to ‘00’, 7644 bytes ofmobile service data within a primary RS frame may be assigned to regionsA/B of the corresponding data group.

TABLE 5 SCCC outer code mode for Region C for Region D PL 00 00 1980 0001 1728 01 00 1242 01 01  990 Others Reserved

Table 5 shows an example of the PL values for each data group within asecondary RS frame, wherein each PL value varies depending upon the SCCCouter code mode, when the RS frame mode value is equal to ‘01’, and whenthe SCCC block mode value is equal to ‘00’. For example, when each SCCCouter code mode value of regions C/D is equal to ‘00’, 1980 bytes ofmobile service data within a secondary RS frame may be assigned toregions C/D of the corresponding data group.

Service Multiplexer

FIG. 18 illustrates a block diagram showing an example of the servicemultiplexer. The service multiplexer includes a controller 110 forcontrolling the overall operations of the service multiplexer, a tableinformation generator 120 for the main service, a RS frame generator130, a TS packet encapsulator 140, and a transport multiplexer 160.

The transport multiplexer 160 may include a main service multiplexer 161and a transport stream (TS) packet multiplexer 162.

At this point, when data is transmitted from the service multiplexer 100to the transmitter 200 using an interface standard, such as asynchronous serial interface for transport of MPEG-2 data (SMPTE-310M),the format of the data is defined to be in an MPEG-2 TS packet format.Therefore, when the data being outputted from the service multiplexer100 does not correspond to a TS packet format, the data cannot betransmitted by using the SMPTE-310M. Herein, the MPEG-2 TS packet isalso referred to as a TS packet.

The present invention is devised to transmit data of an RS frame formobile services from a service multiplexer to a transmitter usingSMPTE-310M. In order to do so, in the embodiment of the presentinvention, the data of the RS frame is MPEG-2 TS-packetized.

Referring to FIG. 18, at least one type of compression-encoded mainservice data and table data generated from the table informationgenerator 120 for the main services are inputted to the main servicemultiplexer 161 of the transport multiplexer 160. According to theembodiment of the present invention, the table information generator 120generates PSI/PSIP table data, which is configured in the form of anMPEG-2 private section. The main service multiplexer 161 respectivelyencapsulates each of the main service data and the PSI/PSIP table data,which are being inputted, to MPEG-2 TS packet formats, therebymultiplexing the encapsulated TS packets and outputting the multiplexedpackets to the TS packet multiplexer 162. Herein, the data packet beingoutputted from the main service multiplexer 162 will hereinafter bereferred to as a main service data packet for simplicity.

The RS frame generator 130 generates an RS frame in any one of theformats shown in FIG. 15, FIG. 17A, and FIG. 17B, thereby outputting thegenerated RS frame to the TS packet encapsulator 140. The TS packetencapsulator 140 TS-packetizes the RS frame generated by the RS framegenerator 130, thereby outputting the TS packet to the TS packetmultiplexer 162.

According to an embodiment of the present invention, a process ofTS-packetizing the RS frame generated, as shown in FIG. 15, will now bedescribed in detail.

The TS packet has a fixed length of 188 bytes. The TS packet broadlyconsists of a TS header (also referred to as an MPEG header), whichcorresponds to an information region, and a payload, which correspondingto a data region. Herein, depending upon whether or not an adaptationfield is included in the TS packet, the payload has a variable lengthranging from 0 to 184 bytes. If the adaptation field is not included inthe TS packet, the payload of the corresponding TS packet has a fixedlength of 184 bytes.

FIG. 19 illustrates a TS packet structure that does not include theadaptation field, wherein the TS packet consists of a 4-byte TS headerand a 184-byte payload. In the 4-byte TS header, 1 byte corresponds to asynchronization byte being assigned with a value of ‘0×47(=01000111)’,in case of an MPEG-2 TS packet. The remaining 3 bytes consists of a1-bit transport error indicator field, a 1-bit payload unit startindicator field, a 1-bit transport priority field, a 13-bit PID field, a2-bit transport scrambling control field, a 2-bit adaptation fieldcontrol field, and a 4-bit continuity counter field. Herein, whether ornot an adaptation field is included in the TS packet can be knownthrough the adaptation field control field.

More specifically, referring to FIG. 19, the transport error indicatorfield indicates the value of ‘1’, when a problem occurs in a transportlayer, e.g., when a packet is lost during the transport.

The payload unit start indicator (hereinafter referred to as PUSI) fieldindicates the beginning of the TS packet. In other words, among aplurality of TS packets, only the PUSI field value of the starting TSpacket is indicated as ‘1’, and the PUSI field value for each of theremaining TS packets is indicated as ‘0’.

The transport priority field decides the priority level of atransmission medium having a PID included therein, when more than onetransmission media having the same PID exist in the TS transmissionpath. Herein, the TS packet having the transport priority field value isset to ‘1’, the corresponding TS packet has the highest priority levelas compared to the remaining TS packets.

The PID field is an identifier that can identify the corresponding TSpacket.

The transport scrambling control field indicates whether or not thecorresponding TS packet has been scrambled.

The adaptation field control field indicates whether or not anadaptation field is included in the corresponding TS packet. Forexample, when the value of the adaptation field control field is equalto either ‘10’ or ‘11’, this indicates that an adaptation field isincluded in the corresponding TS packet. At this point, when the valueof the adaptation field control field is equal to ‘10’, this indicatesthat a payload does not exist in the corresponding TS packet. And, whenthe value of the adaptation field control field is equal to ‘11’, thisindicates that the length of the payload region varies depending uponthe length of the adaptation field. Alternatively, when the value of theadaptation field control field is equal to ‘01’, this indicates that anadaptation field is not included in the corresponding TS packet.Furthermore, the value ‘00’ is not used in the adaptation field controlfield.

The continuity counter field is used in TS packets having the same PID,and the continuity counter field increases by 1 for each packet.However, when the adaptation field control field value is equal to ‘00’or ‘10’, the continuity counter field value should not be increased.

FIG. 20 illustrates a TS packet structure including an adaptation field.More specifically, FIG. 20 illustrates the structure of the TS packetshown in FIG. 19 further including an adaptation field. The adaptationfield is configured of a 2-byte adaptation field (AF) header and N3bytes of stuff bytes. The AF header is configured of an 8-bit AF lengthfield and an 8-bit indicator flag field, so as to indicate the length ofthe corresponding adaptation field. The length of the payload within theTS packet is equal to 182-N3 (wherein N3 corresponds to the stuff bytelength). For example, when the stuff byte length is equal to 182 bytesin the corresponding TS packet, a payload region does not exist.Alternatively, if the stuff byte length is equal to 20 bytes, then thelength of the payload region is equal to 162 bytes.

The TS packet encapsulator 140 divides the RS frame, which is generatedfrom the RS frame generator 130, into a 184-byte payload. Herein, a4-byte TS header (also referred to as an MPEG header) is added to eachpayload, thereby being encapsulated into a 188-byte TS packet.

At this point, the number of TS packets required for TS-packetizing oneRS frame can be calculated by using Equation 3 below.

number of TS packets=└(N×187)/184┘+1   Equation 3

In Equation 3, └X┘ represents a maximum integer not larger than X , andN indicates a number of columns in the corresponding RS frame.

More specifically, in order to know how many TS packets are generatedfrom the RS frame, the size of the RS frame should be known. The size ofthe RS frame varies depending upon the value of N, which corresponds tothe number of columns included in the corresponding RS frame. The valueN may be obtained by applying Equation 2.

Also, when one RS frame is TS-packetized, a first TS packet and a lastTS packet should be known, so that the transmitter 200 can recover theoriginal RS frame. Therefore, the present invention uses the TS headeradded to each payload, in order to indicate the number of TS packetsbeing packetized from a single RS frame, a first (or starting) TSpacket, a last TS packet, and information that can identify (ordistinguish) the RS frame.

More specifically, a PID of the TS header of all TS packets that arebeing encapsulated from the RS frame is set to have a valuecorresponding to an ensemble identifier (ID). For example, if theensemble identifier (ID) corresponding to the RS frame is ‘0×01’, thePID of the TS header in all TS packets that are encapsulated from the RSframe is set to ‘0×0001h’ (i.e., 0000000000001 bit). However, this ismerely exemplary, and, therefore, any value that can identify a TSpacket packetized from the RS frame may be assigned.

Additionally, in the RS frame, a PUSI field value assigned TS header ofa TS packet packetized for the first time is set to ‘1’, and the PUSIfield value of each of the remaining TS packets is set to ‘0’.

More specifically, when the PUSI field value of a TS packet is set to‘1’, this indicates that the first byte of the payload included in thecorresponding TS packet includes the first data byte among the datawithin a single RS frame. Therefore, when a plurality of TS packets isgrouped (or collected) so as to be recovered to the original state bythe transmitter 200, the transmitter 200 may find the TS packet havingthe PUSI value set to ‘1’ and may use the continuity of a continuitycounter field value to find the next TS packets. Then, when thetransmitter 200 adds the found TS packets, the original RS frame may berecovered. If the PUSI value is set to ‘0’, this indicates that thecorresponding TS packet corresponds to a middle portion or end portionof the respective RS frame and not the beginning portion.

Furthermore, the size of an RS frame may correspond to a multiple of 184bytes (i.e., (N×187)Mod184=0) or may not correspond to a multiple of 184bytes (i.e., 0≦(N×187)Mod184≦18). More specifically, when the size of anRS frame does not correspond to a multiple of 184 bytes, this indicatesthat, among the data of an RS frame, the size of a set of data that isto be TS-packetized last is smaller than the size of a payload (i.e.,184 bytes) included in the TS packet.

In the present invention, the method of TS-packetizing the last data ofthe RS frame varies depending upon whether the size of the correspondingRS frame is equal to a multiple of 184 bytes, or depending upon whetherthe size of the corresponding RS frame is not equal to a multiple of 184bytes.

First of all, when the size of the RS frame corresponds to a multiple of184 bytes (i.e., (N×187)Mod184=0), the last data of the RS frame isalready inserted in the payload of the previous TS packet, therebytransmitted to the transmitter 200. In this case, according to theembodiment of the present invention, the last data of the RS frame usesthe last TS packet to notify the transmitter 200 that the transmissionby the previous TS packet has been completed. Therefore, in the last TSpacket, an adaptation field control field of the TS header is set to‘10’, and the entire payload region of the corresponding TS packet isstuffed by using the adaptation field. More specifically, when theadaptation field control field of the TS header is set to ‘10’, apayload region does not exist in the corresponding TS packet. Asdescribed above, the last TS packet having all 182 bytes stuffed, withthe exception of the TS header and the AF header, is used to notify (orindicate) that all data of a single RS frame have been transmitted.

For example, when the number of TS packets calculated by using Equation3 is equal to ‘10’, the last data of the corresponding RS frame isinserted in the payload of the 9^(th) TS packet, no data of thecorresponding RS frame is transmitted to the 10^(th) TS packet. However,the 10^(th) TS packet is used for the purpose of notifying that all dataof the corresponding RS frame have been transmitted. At this point, withthe exception of the last TS packet, the value of the adaptation fieldcontrol field for each TS packet is set to ‘01’.

According to another embodiment of the present invention, when the sizeof the RS frame does not correspond to a multiple of 184 bytes (i.e.,0≦(N×187)Mod184≦183), the last data of the RS frame is included in thepayload of the last TS packet and then transmitted. At this point, sincethe RS frame data that is to be inserted in the payload of the last TSpacket is smaller than 184 bytes, adequate stuffing is required in theremaining region of the corresponding TS packet.

According to the embodiment of the present invention, the value of theadaptation field control field included in the TS header of the last TSpacket is set to ‘11’, and the adaptation field is used to stuff theremaining portion of the last TS packet, thereby inserting the last dataof the RS frame. For example, when the RS frame data that is to betransmitted to the last TS packet corresponds to 162 bytes, 20 bytes ofstuffing data are inserted after a 2-byte AF header of the last TSpacket. Thereafter, 162 bytes of the RS frame data are added immediatelyafter the 20-byte stuffing data. At this point, with the exception ofthe last TS packet, the value of the adaptation field control field foreach TS packet is set to ‘01’.

FIG. 21 illustrates an example of TS-packetizing an RS frame, when thevalue of N is equal to 509. When the value 509 is substituted for thevalue of N in Equation 3, the number of TS packets being packetized fromthe corresponding RS frame is equal to 518, and the size of thecorresponding RS frame is not equal to a multiple of 184 bytes. In thiscase, this indicates that the last 55 data bytes in the corresponding RSframe are transmitted to the 518^(th) TS packet.

As shown in FIG. 21, the value of the TS header corresponding to thefirst TS packet, wherein the first data of the RS frame is to beincluded, is equal to 0×47000110h. This is because the PUSI field valueof the first TS packet is set to ‘1b’, the synchronization byte fieldvalue to ‘01000111b’ (i.e., 0×47h), the PID field value to‘0000000000001b’, and the adaptation field control field value to ‘01b’.Furthermore, it is assumed that each of the transport error indicatorfield value and the transport priority field value is set to ‘0b’, thatthe transport scrambling control field is set to ‘0b’, and that thecontinuity counter field value is set to ‘0000b’ (i.e., 0×0h).

Conversely, the value of the TS header corresponding to the last TSpacket, wherein the last data of the RS frame is to be included, isequal to 0×4700013Bh. This is because the PUSI field value of the lastTS packet is set to ‘0b’, the synchronization byte field value to‘0×47h’, the PID field value to ‘0000000000001b’, and the adaptationfield control field value to ‘11b’. Furthermore, it is assumed that eachof the transport error indicator field value and the transport priorityfield value is set to ‘0b’, that the transport scrambling control fieldis set to ‘00b’, and that the continuity counter field value is set to arandom (or arbitrary) value (e.g., 0×Bh) so that the last TS packet canhave a continuity with the previous TS packet. Then, the regionfollowing the TS header of the last TS packet is divided into a 129-byteadaptation field region and a 55-byte payload region. Among the 129bytes of the adaptation field region, 2 bytes are assigned to the AFheader so as to indicate the length of the adaptation field, and theremaining 127 bytes of the adaptation field region are stuffed. Morespecifically, referring to FIG. 21, the region marked as ‘stuffing’corresponds to the adaptation field.

FIG. 22 illustrates a flow chart showing an exemplary process ofTS-packetizing the RS frame according to the present invention.

In order to obtain the size of the RS frame, an N value is calculated byusing Equation 2 (S181). Then, by applying the calculated N value toEquation 3, the number of TS packets that are to be packetized from theRS frame is calculated (S812). In step 812, when the size of the RSframe does not correspond to a multiple of 184 bytes, the number ofstuffing bytes that are to stuff the last TS packet is also calculated.Subsequently, the RS frame is divided into 184-byte units, and 4-byte TSheader is assigned to each 184-byte unit (S183 to S195).

At this point, when the size of the corresponding RS frame is a multipleof 184, the RS frame is divided into a plurality of 184-byte units,wherein the number of 184-byte units corresponds to the total number ofTS packets obtained in step 182 subtracting ‘1’. In this case, theadaptation field control field value of the TS header included in thelast TS packet is set to ‘10’, and the 182 bytes following the 2-byte AFheader are filled with 182 bytes of stuffing data.

Meanwhile, when the size of the corresponding RS frame is not equal to amultiple of 184, the RS frame is divided into a plurality of 184-byteunits, wherein the number of 184-byte units corresponds to the totalnumber of TS packets obtained in step 182 subtracting ‘1’. Accordingly,data having a size smaller than 184 bytes remain in the RS frame, andthe corresponding data is included in the last TS packet. In this case,the adaptation field control field value of the TS header included inthe last TS packet is set to ‘11’, and the adaptation field is used tofill the remaining portion of the RS frame is filled with stuffing data.For example, when the data of the RS frame that is to be included in thelast TS packet corresponds to 55 bytes, the remaining 127 bytesexcluding the 2-byte AF header within the adaptation field are filledwith stuffing data, and the next 55 bytes are filled with the RS framedata.

More specifically, when the RS frame is divided into 184-byte units,each field value of the TS header that is to be added to each 184-byteunit varies depending upon the position of the respective TS packet.And, each time the RS frame is divided into 184-byte units is counted.In the description of the present invention, the count value will bereferred to as a TS packet count value. The maximum TS packet countvalue corresponds to └(N×187)/184┘+1, and the TS packet count is resetwhen the TS-packetizing of the corresponding RS frame is completed.Settings for the field value of the TS header being added to each184-byte unit will now be described in detail.

More specifically, in step 183, the synchronization byte field value ofthe corresponding TS packet is set to ‘0×47h’, and the continuitycounter field value is set to a random value so that the correspondingTS packet can have a continuity with the previous TS packet. Then, eachof the transport error indicator field value and the transport priorityfield value is set to ‘0b’, and the transport scrambling control fieldvalue is set to ‘00b’. Thereafter, it is verified whether the data thatis to be included in the TS packet includes the first 184 bytes of therespective RS frame (S184).

When it is verified that the data that is to be included in the TSpacket contains the first 184 bytes of the RS frame, the PUSI fieldvalue of the TS packet is set to ‘1b’ (S185). However, when the datathat is to be included in the TS packet does not contain the first 184bytes of the RS frame, the PUSI field value of the TS packet is set to‘0b’ (S186). Subsequently, the PID field value of the TS packet sets anensemble identifier corresponding to the respective RS frame. Forexample, when the ensemble identifier is ‘0×01h’, the PID value becomes‘0×0001h’ (i.e., 0000000000001b).

After performing step 187, it is verified whether the TS packet countvalue is equal to the number of TS packets (i.e., └(N×187)/184┘+1)calculated in step 182 (S188). This is because the method ofTS-packetizing the last data of the RS frame varies depending uponwhether or not the size of the corresponding RS frame is a multiple of184. More specifically, in step 188, when the TS packet count value isnot equal to the number of TS packets, the adaptation field controlfield value within the TS header of the corresponding TS packet is setto ‘01’ (S189). And, the payload region is filled with the 184-byte RSframe data (S190). Herein, step 189 and step 190 correspond to thepacketizing process before the last TS packet.

In step 188, when the TS packet count value is equal to the number of TSpackets, it is verified whether or not the size of the corresponding RSframe is a multiple of 184 (S191). More specifically, in case of thelast TS packet, it is verified whether the size of the corresponding RSframe is a multiple of 184. Then, when it is verified that the size ofthe RS frame is a multiple of 184, in step 191, the adaptation fieldcontrol field value in the TS header of the last TS packet is set to‘10’ (S192), and the region corresponding to 182 bytes subsequent to the2-byte AF header within the adaptation field is filled with stuffingdata (S193).

Furthermore, when it is verified that the size of the RS frame is not amultiple of 184, in step 191, among the RS frame data, data having asize smaller than 184 bytes should be included in the last TS packet.For this, the value of the adaptation field control field of the TSheader included in the last TS header is set to ‘11’ (S194), and theremaining portion of the last TS packet excluding the last data size ofthe RS frame is filled with stuffing data by using the adaptation field(S195) . For example, if the RS frame data that is to be included in thelast TS packet is 55 bytes, the remaining 127 bytes excluding the 2-byteAF header within the adaptation field are filled with stuffing data, andthe next 55 bytes are filled with RS frame data.

Referring to the flow chart shown in FIG. 22, it can be known that inorder to TS-packetize a series of continuous RS frames, an RS framechecking step is performed only once at the beginning, and then a TSpacket header step and a TS packet payload step are serially performed.

As described above, the RS frame is encapsulated to a plurality of TSpackets from the TS packet encapsulator 140, and the encapsulated TSpackets are outputted to the TS packet multiplexer 162 of the transportmultiplexer 160. Hereinafter, the TS packets being outputted from the TSpacket encapsulator 140 will be referred to as mobile service datapackets for simplicity.

At this point, for the transmitter 200 to identify and process the mainservice data packet and mobile service data packet, identificationinformation is required. According to an embodiment of the presentinvention, the identification process is performed by using the packetidentifier (PID) assigned to the main service data packet and the mobileservice data packet.

According to another embodiment of the present invention, by modifyingthe synchronization bytes within the header of the mobile service datapacket, the identification process may be performed by using thesynchronization byte value of the corresponding service data packet. Forexample, by directly outputting the synchronization byte of the mainservice data packet without changing its value (e.g., 0×47), which isprovided (or defined) in the ISO/IEC 13818-1, and by modifying andoutputting the synchronization byte of the mobile service data packet,the main service data packet and the mobile service data packet can bedistinguished (or identified).

Alternatively, by modifying and outputting the synchronization byte ofthe main service data packet, and by outputting the synchronization byteof the mobile service data packet without modification, the main servicedata packet and the mobile service data packet can also bedistinguished. The synchronization byte may be modified by using aplurality of methods. For example, the synchronization byte may bemodified by performing bitwise inversion or by performing partialinversion on a selection of data bits.

As described above, any information that can identify (or distinguish)the main service data packet and the mobile service data packet may beused as the identification information. Therefore, the present inventionwill not be limited only to the examples given herein.

Meanwhile, the transport multiplexer used in the existing digitalbroadcasting system can be used as the transport multiplexer 160.Namely, in order to multiplex the mobile service data with the mainservice data and transmit them, a data rate of the main service islimited to a data rate of M Mbps, and L Mbps corresponding to the otherdata rate is allocated to the mobile service output from the TS packetencapsulator 140. In this case, the existing transport multiplexer canbe used as it is without any change. Then, the TS packet multiplexer 162multiplexes the main service data packets output from the main servicemultiplexer 161 at a data rate of M Mbps with the mobile service datapackets output from the TS packet encapsulator 140 at a data rate of LMbps and transmits the multiplexed data packets to the transmitter.

However, there may be a case where the output data rate of the TS packetmultiplexer 162 does not reach 19.39 Mbps even though the output datarate L Mbps of the TS packet encapsulator 140 and the output data rate MMbps of the main service multiplexer 161 are added to each other.

In this case, the TS packet multiplexer 162 receives null data packetsof a data rate of (19.39-M-L) Mbps, multiplexes the null data packetswith the main service data packets and the mobile service data packets,and output the multiplexed data packets. In this case, theidentification information is included in the null data packets so thatthe transmitter can identify the null data packets. In this case, theoutput data rate of the TS packet multiplexer 162 can be adjusted to19.39 Mbps.

In other words, since the mobile service data are extended by additionalencoding in the transmitter, even though the TS packet encapsulator 140obtains data of L Mbps by packetizing RS frame into TS packets, if thedata rate of L Mbps is added to the output data rate of the main servicemultiplexer 161, the output data rate of the TS packet multiplexer 162may be smaller than 19.39 Mbps. In this case, the null data packets areadded to the service data packets by the difference so that the outputdata rate of the TS packet multiplexer 162 is adjusted to 19.39 Mbps.

At this point, the transmitter 200 discards the null data packetstransmitted from the service multiplexer 100 instead of transmitting thenull data packets.

Further, in order to allow the transmitter 200 to discard the null datapackets transmitted from the service multiplexer 100 instead oftransmitting them, identification information for identifying the nulldata packet is required. Herein, the identification information may usevalues pre-decided in accordance with an agreement between thetransmitting system and the receiving system. For example, the value ofthe synchronization byte within the header of the null data packet maybe modified so as to be used as the identification information.Alternatively, a transport_error_indicator flag may also be used as theidentification information.

In the description of the present invention, an example of using thetransport_error_indicator flag as the identification information will begiven to describe an embodiment of the present invention. In this case,the transport_error_indicator flag of the null data packet is set to‘1’, and the transport_error_indicator flag of the remaining datapackets are reset to ‘0’, so as to identify the null data packet. In thepresent invention, any type of identification information foridentifying the null data packets may be used. Therefore, the scope ofthe present invention is not limited only to the examples set forth inthe description of the present invention.

The controller 110 controls the RS frame generation of the RS framegenerator 130, the TS packetization of TS packet encapsulator 140, themultiplexing processed performed by the main service multiplexer 161 andthe TS packet multiplexer 162 of the transport multiplexer 160, and alsocontrols the null data packet generation.

Transmitter

FIG. 23 illustrates a block diagram showing an example of thetransmitter 200 according to an embodiment of the present invention.Herein, the transmitter 200 includes a controller 201, a demultiplexer210, a packet jitter mitigator 220, a pre-processor 230, a packetmultiplexer 240, a post-processor 250, a synchronization (sync)multiplexer 260, and a transmission unit 270.

Herein, when a data packet is received from the service multiplexer 100,the demultiplexer 210 should identify whether the received data packetcorresponds to a main service data packet, a mobile service data packet,or a null data packet.

For example, the demultiplexer 210 uses the PID within the received datapacket so as to identify the main service data packet and the mobileservice data packet. Then, the demultiplexer 210 uses atransport_error_indicator field to identify the null data packet.

The main service data packet identified by the demultiplexer 210 isoutputted to the packet jitter mitigator 220, the mobile service datapacket is outputted to the pre-processor 230, and the null data packetis discarded.

The pre-processor 230 groups a plurality of mobile service data packetsdemultiplexed and outputted from the demultiplexer 210, therebyrecovering the original RS frame. The RS frame refers to the TS headerof each mobile service data packet, so as to perform the recoveryprocess. At this point, the TS header of the mobile service data packetis removed, and the payload of each mobile service data is grouped torecover the RS frame. Thereafter, additional encoding is performed inthe recovered RS frame unit. Furthermore, the pre-processor 230 performa data group configuring process so that a corresponding data can bepositioned in a specific position of a transmission frame depending uponthe usage of the data that are to be transmitted. Then, known data,mobile service data, RS parity data, MPEG header, and so on are assignedto predetermined regions within the data group. This is to enable themobile service data to swiftly and strongly respond to noise and channelchanges. Pre-processor in the transmitter

FIG. 24 illustrates a block view showing the structure of apre-processor 230 according to an embodiment of the present invention.Herein, the pre-processor 230 includes an MH frame encoder 301, a blockprocessor 302, a group formatter 303, a signaling encoder 304, and apacket formatter 305. In the pre-processor 230 having theabove-described structure, the MH frame encoder 301 groups a pluralityof mobile service data packets being inputted through the demultiplexer210, so as to recover the original RS frame. Thereafter, an encodingprocess for error correction is performed in the recovered RS frameunit.

FIG. 25 illustrates an exemplary process of recovering the RS frame froma plurality of mobile service data packets, when the value of N is equalto 509.

Referring to FIG. 25, it is assumed that the value assigned to the TSheader in each mobile service data packet is the same as the valueassigned to the TS header of each TS packet in the TS-packetizingprocess shown in FIG. 21. First of all, mobile service data packets,which are set to have PID field values identical to ensemble identifier(ID) values corresponding to the RS frame that is to be recovered, areextracted and stored. According to an embodiment of the presentinvention, the PID field value of each TS header is set to have the samevalue as the ensemble identifier.

Then, among the extracted mobile service data packets, when dataincluded in payload region of each mobile service packets from themobile service data packet having the PUSI field value of the respectiveTS header set to ‘1’ to the mobile service data packet having theadaptation field control field of the respective TS header set to ‘10’or ‘11’ are sequentially grouped, one RS frame is recovered. At thispoint, since the adaptation field region of the mobile service datapacket having its adaptation field control field value set to ‘10’ or‘11’ does not correspond to a payload region, the stuffing data beinginserted in the adaptation field region are not used as the RS framedata. Furthermore, when the RS frame recovery is completed, the TSheader of each mobile service data packet that has transmitted the RSframe data is also removed. Then, the TS header of each mobile servicedata packet configuring the RS frame is assigned with the same PIDvalue, i.e., each of the corresponding TS headers is given an ensembleidentifier corresponding to the RS frame.

More specifically, when the PUSI field value in the TS header of amobile service data packet is set to ‘1’, this indicates the payload ofthe corresponding mobile service data packet includes the 1^(st) databyte among the data of an RS frame. As described above, by using thePUSI field value of the TS header, the system may know from which mobileservice data packet, among the extracted mobile service data packets,the 1^(st) data byte of an RS frame begins. At this point, theadaptation field control field value should be set to ‘01’. Morespecifically, an adaptation field region does not exist in thecorresponding mobile service data packet.

Among the extracted mobile service data packets, the mobile service datapacket having the PUSI field value of the TS header set to ‘1’ is found(or located). Then, by using the continuity of the continuity counterfield values, the mobile service data packets following the primarilylocated mobile service data packet are sequentially located. At thispoint, the PUSI field value of the TS header in the next mobile servicedata packets should be set to ‘0’, and the PID value of the next mobileservice data packets should be identical to the PID values of the mobileservice data packets, which have the PUSI field value set to ‘1’.Furthermore, the adaptation field control field value should be set to‘01’.

This process is performed until the mobile service data packet havingthe respective adaptation field control field value set to ‘10’ or ‘11’is located. Thus, mobile service data packets corresponding to a singleRS frame are all located (or found). More specifically, when the mobileservice data packet has the adaptation field control field value of ‘10’or ‘11’, this indicates that the corresponding mobile service datapacket is the last mobile service data packet of the corresponding RSframe.

At this point, when the adaptation field control field value of a mobileservice data packet is set to ‘10’, this indicates that thecorresponding mobile service data does not include a payload region andthat the remaining 182 bytes of the adaptation field excluding the AFheader are filled with stuffing data. More specifically, the last dataof the RS frame is already inserted in the payload of the previousmobile service data packet and received. Therefore, when the mobileservice data packet having its adaptation field control field value setto ‘10’ is extracted, the MH frame encoder 301 may be informed that thelast data of the RS frame, which is to be recovered, has already beenreceived by the previous mobile service data packet.

Additionally, when the adaptation field control field value of a mobileservice data packet is set to ‘11’, an adaptation field region and apayload region are both included in the respective mobile service datapacket. Herein, the last data of the corresponding RS frame is includedin the payload region. At this point, the last data of the RS frame,which is to be inserted in the payload of the corresponding mobileservice data packet, is smaller than 184 bytes. And, the remaining databytes from the 182 bytes excluding the last data of the RS frame arefilled with stuffing data in the adaptation field region.

As described above, when the data included in the payload regionstarting from the extracted (or located) starting mobile service datapacket to the extracted (or located) last mobile service data packet aresequentially grouped, a single RS frame can be recovered. Also, whencomparing the recovered RS frame size to the RS frame size based uponthe N value, the system can verify whether or not a complete RS framehas been recovered.

FIG. 26 illustrates a flow chart showing the process of recovering an RSframe from a plurality of mobile service data packets according to anembodiment of the present invention.

Firstly, an ensemble identifier corresponding to an RS frame that is tobe recovered is selected as the PID field value (S351). Then, when themobile service data packet is received (S352), it is verified whether ornot the PID field value of the received mobile service data packet isidentical to the selected PID field value (S353). If it is determined instep 353 that the PIDs are not identical to each other, this indicatesthat the respective mobile service data packet does not correspond to adesired (or requested) mobile service data packet. Therefore, theprocess step returns to step 352 so as to receive another mobile servicedata packet.

Thereafter, if it is determined that the PIDs are identical to eachother, it is determined whether or not a mobile service data packethaving the PUSI field value of the TS header set to ‘1’ has already beenreceived (S354). More specifically, if the PUSI field value of the TSheader in the mobile service data packet is set to ‘1’, this indicatesthat the payload of the corresponding mobile service data packetincludes the 1^(st) data byte among the data of the RS frame that is tobe recovered.

In step 354, when a mobile service data packet having the PUSI fieldvalue of the TS header set to ‘1’ has already been received, the processstep moves on to step 356. In step 356, the received mobile service datapacket is stored. At this point, the PUSI field value of the TS headercorresponding to the stored mobile service data packet is set to ‘0’.Furthermore, the adaptation field control field value is set to any oneof ‘01’, ‘10’, and ‘11’. Alternatively, in step 354, when a mobileservice data packet having the PUSI field value of the TS header set to‘1’ has not yet been received, the process step moves on to step 355,thereby verifying whether or not the PUSI field value of the TS headerincluded in the currently received mobile service data packet is equalto ‘1’.

In the step 355, when it is determined that the PUSI field value of theTS header included in the currently received mobile service data packetis not equal to ‘1’, this indicates that the currently received mobileservice data packet does not correspond to a desired (or requested)mobile service data packet. Therefore, the process step returns to step352 so as to receive another mobile service data packet.

Conversely, in step 355, when it is determined that the PUSI field valueof the TS header included in the currently received mobile service datapacket is equal to ‘1’, this indicates that the currently receivedmobile service data packet includes the 1^(st) data byte among the dataof the RS frame that is to be recovered. Therefore, the received mobileservice data packet is stored (S356). At this point, the adaptationfield control field value is set to ‘01’.

In step 356, when the received mobile service data is stored, it isverified whether or not the adaptation field control field value of theTS header included in the received mobile service data packet is set to‘10’ or ‘11’ (S357). Namely, it is verified whether or not the receivedmobile service data is the last mobile service data configuring the RSframe that is to be recovered.

In step 357, when the adaptation field control field value is not equalto ‘10’ or ‘11’, this indicates that the stored mobile service datapacket does not correspond to the last mobile service data packet.Therefore, the process step returns to step 352 so as to further receivemobile service data packets.

Alternatively, in step 357, when the adaptation field control fieldvalue is equal to ‘10’ or ‘11’, this indicates that all mobile servicedata packets starting from the 1St mobile service data packet to thelast mobile service data packet of the RS frame that is to be recoveredare stored. Accordingly, when the data inserted in the payload of eachof the stored mobile service data packets are grouped, an RS frame canbe recovered (S358).

At this point, a step verifying whether or not the RS frame has beenproperly recovered may be further included.

More specifically, it is determined whether or not the size of the RSframe recovered in step 358 is equal to N×187 bytes (S359). If the sizeof the recovered RS frame is equal to N×187 bytes, this indicates thatthe recovery of the RS frame has been properly performed. Therefore, anerror correction encoding process is performed on the recovered RS frame(S360).

However, if the size of the recovered RS frame is not equal to N×187bytes, this indicates that the RS frame recovery process has not beenproperly performed. Therefore, the recovered RS frame is discarded (ordeleted) (S361).

Referring to the flow chart of FIG. 26, the MH frame encoder 301 firstinputs initial PID settings and, then, repeatedly performs the remainingprocess steps, thereby being able to sequentially recover RS frameshaving the same ensemble from the received mobile service data packets.

At this point, the MH frame encoder 301 may include at least one RSframe encoder. More specifically, the number of RS frame encoders thatare provided in parallel may be equal to the number of parades withinthe MH frame. As described above, the MH frame corresponds to a basictime cycle for transmitted at least one parade. Herein, each parade isconfigured of one or two RS frames.

FIG. 27 is a conceptual block diagram showing an example of the MH frameencoder 301. The MH frame encoder 301 may include an input demultiplexer(DEMUX) 309, M number of RS frame encoders 310 to 31M-1, and an outputmultiplexer (MUX) 320. Herein, M represent the number of paradesincluded in one MH frame. The input demultiplexer 309 output theinputted mobile service data packet to a corresponding RS frame encoderamong M number of RS frame encoders in ensemble units.

For example, the demultiplexer 309 may decide an output path of themobile service data packet based upon the TS header of the inputtedmobile service data packet. At this point, the ensemble may be mapped tothe RS frame encoder or a parade. For example, when one parade isconfigured of one RS frame, each ensemble, RS frame, and parade may bemapped to be in a 1:1:1 (or one-to-one-to-one) correspondence.

According to an embodiment of the present invention, each RS frameencoder groups a plurality of mobile service data packets, each havingthe corresponding ensemble identifier as the respective PID field value,so as to configure an RS frame and, then, to perform an error correctionencoding process in RS frame units. Also, each RS frame encoder dividesthe error-correction-encoded RS frame into a plurality of portions, inorder to assign the error-correction-encoded RS frame data to aplurality of data groups.

Based upon the RS frame mode of Table 1, data within one RS frame may beassigned either to all of regions A/B/C/D within multiple data groups,or to at least one of regions A/B and regions C/D within multiple datagroups.

When the RS frame mode value is equal to ‘01’, i.e., when the data ofthe primary RS frame are assigned to regions A/B of the correspondingdata group and data of the secondary RS frame are assigned to regionsC/D of the corresponding data group, each RS frame encoder configures aprimary RS frame and a secondary RS frame for each parade. Conversely,when the RS frame mode value is equal to ‘00’, when the data of theprimary RS frame are assigned to all of regions A/B/C/D, each RS frameencoder configures a RS frame (i.e., a primary RS frame) for eachparade.

Also, each RS frame encoder divides each RS frame into several portions.Each portion of the RS frame is equivalent to a data amount that can betransmitted by a data group. The output multiplexer (MUX) 320multiplexes portions within M number of RS frame encoders 310 to 310M-1and then outputted to the block processor 302. For example, if oneparade transmits two RS frames, portions of primary RS frames within Mnumber of RS frame encoders 310 to 310M-1 are multiplexed and outputted.Thereafter, portions of secondary RS frames within M number of RS frameencoders 310 to 310M-1 are multiplexed and transmitted.

The input demultiplexer (DEMUX) 309 and the output multiplexer (MUX) 320operate based upon the control of the controller 201. The controller 201may provide necessary (or required) FEC modes to each RS frame encoder.The FEC mode includes the RS code mode, which will be described indetail in a later process.

FIG. 28 illustrates a detailed block diagram of an RS frame encoderamong a plurality of RS frame encoders within an MH frame encoder.

The primary encoder 410 includes a data randomizer 411, an RS-CRCencoder 412, and an RS frame divider 413. Herein, the data randomizer411 may be omitted from the primary encoder 410.

The secondary encoder 420 may also include a data randomizer 421, anRS-CRC encoder 422, and an RS frame divider 423. Similarly, the datarandomizer 421 may also be omitted from the secondary encoder 420.

According to an embodiment of the present invention, each of the datarandomizers 411 and 421 are omitted from the primary encoder 410 and thesecondary encoder 420. However, according to another embodiment of thepresent invention, if the data randomizers 411 and 421 are not omitted,the RS frame is recovered from the randomized mobile service datapackets.

More specifically, when a randomizing process is performed on a mobileservice data packet by the data randomizer 411 of the primary encoder410, a randomizing process on the respective mobile service data packetthat is to be performed by the data randomizer 251 of the post-processor250 may be omitted.

The data randomizer 411 may discard the synchronization byte within themobile service data packet, thereby performing the randomizing process.Alternatively, the randomizing process may also be performed withouthaving to discard the synchronization byte. Such modification orvariation may be selected by the system designer. According to anembodiment of the present invention, when performing the randomizingprocess, the randomizing process may be performed without discarding thesynchronization byte within the corresponding mobile service datapacket.

The RS-CRC encoder 412 configures (or recovers) an RS framecorresponding to a primary ensemble from the input mobile service datapackets. Then, the RS-CRC encoder 412 uses at least one of aReed-Solomon (RS) code and a cyclic redundancy check (CRC) code in RSframe units, so as to perform forward error correction (FEC) encoding onthe recovered RS frame, thereby outputting the processed RS frame to theRS frame divider 413. More specifically, the RS-CRC encoder 412 groups(or gathers) data that are inserted in the payload of each mobileservice data packet, so as to configure an RS frame. Then, the RS-CRCencoder 412 performs at least one of an error correction encodingprocess and an error detection encoding process in RS frame units.Accordingly, robustness may be provided to the mobile service data,thereby scattering group error that may occur during changes in afrequency environment, thereby enabling the mobile service data torespond to the frequency environment, which is extremely vulnerable andliable to frequent changes.

Also, the RS-CRC encoder 412 groups a plurality of RS frame so as tocreate a super frame, thereby performing a row permutation process insuper frame units. The row permutation process may also be referred toas a “row interleaving process”. Hereinafter, the process will bereferred to as “row permutation” for simplicity. In the presentinvention, the row permutation process may be omitted.

More specifically, when the RS-CRC encoder 412 performs the process ofpermuting each row of the super frame in accordance with apre-determined rule, the position of the rows within the super framebefore and after the row permutation process is changed. If the rowpermutation process is performed by super frame units, and even thoughthe section having a plurality of errors occurring therein becomes verylong, and even though the number of errors included in the RS frame,which is to be decoded, exceeds the extent of being able to becorrected, the errors become dispersed within the entire super frame.Thus, the decoding ability is even more enhanced as compared to a singleRS frame.

At this point, as an example of the present invention, RS-encoding isapplied for the error correction encoding process, and a cyclicredundancy check (CRC) encoding is applied for the error detectionprocess in the RS-CRC encoder 412. When performing the RS-encoding,parity data that are used for the error correction are generated. And,when performing the CRC encoding, CRC data that are used for the errordetection are generated.

The CRC data generated by CRC encoding may be used for indicatingwhether or not the mobile service data have been damaged by the errorswhile being transmitted through the channel. In the present invention, avariety of error detection coding methods other than the CRC encodingmethod may be used, or the error correction coding method may be used toenhance the overall error correction ability of the receiving system.

Herein, the RS-CRC encoder 412 refers to a pre-determined transmissionparameter provided by the controller so as to perform operationsincluding RS frame configuration, RS encoding, CRC encoding, super frameconfiguration, and row permutation in super frame units.

FIG. 29 illustrates a process of one or two RS frame being divided intoseveral portions, based upon an RS frame mode value, and a process ofeach portion being assigned to a corresponding region within therespective data group. According to an embodiment of the presentinvention, the data assignment within the data group performs in thegroup formatter 303.

More specifically, FIG. 29( a) shows an example of the RS frame modevalue being equal to ‘00’. Herein, only the primary encoder 410 of FIG.28 operates, thereby forming one RS frame for one parade. Then, the RSframe is divided into several portions, and the data of each portion areassigned to regions A/B/C/D within the respective data group.

FIG. 29( b) shows an example of the RS frame mode value being equal to‘01’. Herein, both the primary encoder 410 and the secondary encoder 420of FIG. 28 operate, thereby forming two RS frames for one parade, i.e.,one primary RS frame and one secondary RS frame. Then, the primary RSframe is divided into several portions, and the secondary RS frame isdivided into several portions. At this point, the data of each portionof the primary RS frame are assigned to regions A/B within therespective data group. And, the data of each portion of the secondary RSframe are assigned to regions C/D within the respective data group.

Detailed Description of the RS Frame

FIG. 30( a) illustrates an example of an RS frame being generated fromthe RS-CRC encoder 412 according to the present invention.

When the RS frame is created, as shown in FIG. 30( a), the RS-CRCencoder 412 performs a (Nc,Kc)-RS encoding process on each column, so asto generate Nc-Kc(=P) number of parity bytes. Then, the RS-CRC encoder412 adds the newly generated P number of parity bytes after the verylast byte of the corresponding column, thereby creating a column of(187+P) bytes. Herein, as shown in FIG. 30( a), Kc is equal to 187(i.e., Kc=187), and Nc is equal to 187+P (i.e., Nc=187+P). Herein, thevalue of P may vary depending upon the RS code mode. Table 6 below showsan example of an RS code mode, as one of the RS encoding information.

TABLE 6 RS code mode RS code Number of Parity Bytes (P) 00 (211, 187) 2401 (223, 187) 36 10 (235, 187) 48 11 Reserved Reserved

Table 6 shows an example of 2 bits being assigned in order to indicatethe RS code mode. The RS code mode represents the number of parity bytescorresponding to the RS frame.

For example, when the RS code mode value is equal to ‘10’,(235,187)-RS-encoding is performed on the RS frame of FIG. 30( a), so asto generate 48 parity data bytes. Thereafter, the 48 parity bytes areadded after the last data byte of the corresponding column, therebycreating a column of 235 data bytes.

When the RS frame mode value is equal to ‘00’ in Table 1 (i.e., when theRS frame mode indicates a single RS frame), only the RS code mode of thecorresponding RS frame is indicated. However, when the RS frame modevalue is equal to ‘01’ in Table 1 (i.e., when the RS frame modeindicates multiple RS frames), the RS code mode corresponding to aprimary RS frame and a secondary RS frame. More specifically, it ispreferable that the RS code mode is independently applied to the primaryRS frame and the secondary RS frame.

When such RS encoding process is performed on all N number of columns, aRS frame having the size of N(row)×(187+P)(column) bytes may be created,as shown in FIG. 30( b).

Each row of the RS frame is configured of N bytes. However, dependingupon channel conditions between the transmitting system and thereceiving system, error may be included in the RS frame. When errorsoccur as described above, CRC data (or CRC code or CRC checksum) may beused on each row unit in order to verify whether error exists in eachrow unit.

The RS-CRC encoder 412 may perform CRC encoding on the mobile servicedata being RS encoded so as to create (or generate) the CRC data. TheCRC data being generated by CRC encoding may be used to indicate whetherthe mobile service data have been damaged while being transmittedthrough the channel.

The present invention may also use different error detection encodingmethods other than the CRC encoding method. Alternatively, the presentinvention may use the error correction encoding method to enhance theoverall error correction ability of the receiving system.

FIG. 30( c) illustrates an example of using a 2-byte (i.e., 16-bit) CRCchecksum as the CRC data. Herein, a 2-byte CRC checksum is generated forN number of bytes of each row, thereby adding the 2-byte CRC checksum atthe end of the N number of bytes. Thus, each row is expanded to (N+2)number of bytes. Equation 4 below corresponds to an exemplary equationfor generating a 2-byte CRC checksum for each row being configured of Nnumber of bytes.

g(x)=x ¹⁶ +x ¹² +x ⁵+1   Equation 4

The process of adding a 2-byte checksum in each row is only exemplary.Therefore, the present invention is not limited only to the exampleproposed in the description set forth herein. As described above, whenthe process of RS encoding and CRC encoding are completed, the(N×187)-byte RS frame is expanded to a (N+2)×(187+P)-byte RS frame.Based upon an error correction scenario of a RS frame expanded asdescribed above, the data bytes within the RS frame are transmittedthrough a channel in a row direction. At this point, when a large numberof errors occur during a limited period of transmission time, errorsalso occur in a row direction within the RS frame being processed with adecoding process in the receiving system. However, in the perspective ofRS encoding performed in a column direction, the errors are shown asbeing scattered. Therefore, error correction may be performed moreeffectively. At this point, a method of increasing the number of paritydata bytes (P) may be used in order to perform a more intense errorcorrection process. However, using this method may lead to a decrease intransmission efficiency. Therefore, a mutually advantageous method isrequired. Furthermore, when performing the decoding process, an erasuredecoding process may be used to enhance the error correctionperformance.

Additionally, the RS-CRC encoder 412 according to the present inventionalso performs a row permutation (or interleaving) process in super frameunits in order to further enhance the error correction performance whenerror correction the RS frame.

FIG. 31( a) to FIG. 31( d) illustrates an example of performing a rowpermutation process in super frame units according to the presentinvention. More specifically, G number of RS frames RS-CRC-encoded isgrouped to form a super frame, as shown in FIG. 31( a). At this point,since each RS frame is formed of (N+2)×(187+P) number of bytes, onesuper frame is configured to have the size of (N+2)×(187+P)×G bytes.

When a row permutation process permuting each row of the super frameconfigured as described above is performed based upon a pre-determinedpermutation rule, the positions of the rows prior to and after beingpermuted (or interleaved) within the super frame may be altered. Morespecifically, the i^(th) row of the super frame prior to theinterleaving process, as shown in FIG. 31( b), is positioned in thej^(th) row of the same super frame after the row permutation process, asshown in FIG. 31( c). The above-described relation between i and j canbe easily understood with reference to a permutation rule as shown inEquation 5 below.

j=G(i mod(187+P))+└i/(187+P)┘  Equation 5

i=(187+P)(j mod G)+└j/G┘

where 0≦i, j≦(187+P)G−1; or

where 0≦i, j≦(187+P)G

Herein, each row of the super frame is configured of (N+2) number ofdata bytes even after being row-permuted in super frame units.

When all row permutation processes in super frame units are completed,the super frame is once again divided into G number of row-permuted RSframes, as shown in FIG. 31( d), and then provided to the RS framedivider 413. Herein, the number of RS parity bytes and the number ofcolumns should be equally provided in each of the RS frames, whichconfigure a super frame. As described in the error correction scenarioof a RS frame, in case of the super frame, a section having a largenumber of error occurring therein is so long that, even when one RSframe that is to be decoded includes an excessive number of errors(i.e., to an extent that the errors cannot be corrected), such errorsare scattered throughout the entire super frame. Therefore, incomparison with a single RS frame, the decoding performance of the superframe is more enhanced.

The above description of the present invention corresponds to theprocesses of forming (or creating) and encoding an RS frame, when a datagroup is divided into regions A/B/C/D, and when data of an RS frame areassigned to all of regions A/B/C/D within the corresponding data group.More specifically, the above description corresponds to an embodiment ofthe present invention, wherein one RS frame is transmitted using oneparade. In this embodiment, the secondary encoder 420 does not operate(or is not active).

Meanwhile, 2 RS frames are transmitting using one parade, the data ofthe primary RS frame may be assigned to regions A/B within the datagroup and be transmitted, and the data of the secondary RS frame may beassigned to regions C/D within the data group and be transmitted. Atthis point, the primary encoder 410 receives the mobile service datapackets that are to be assigned to regions A/B within the data group, soas to form the primary RS frame, thereby performing RS-encoding andCRC-encoding. Similarly, the secondary encoder 420 receives the mobileservice data packets that are to be assigned to regions C/D within thedata group, so as to form the secondary RS frame, thereby performingRS-encoding and CRC-encoding. More specifically, the primary RS frameand the secondary RS frame are created independently.

FIG. 32 illustrates examples of receiving the mobile service datapackets that are to be assigned to regions A/B within the data group, soas to form the primary RS frame, and receives the mobile service datapackets that are to be assigned to regions C/D within the data group, soas to form the secondary RS frame, thereby performing error correctionencoding and error detection encoding on each of the first and secondaryRS frames.

More specifically, FIG. 32( a) illustrates an example of the RS-CRCencoder 412 of the primary encoder 410 receiving mobile service datapackets of the primary ensemble that are to be assigned to regions A/Bwithin the corresponding data group, so as to create an RS frame havingthe size of N1(row)×187(column). Then, in this example, the primaryencoder 410 performs RS-encoding on each column of the RS frame createdas described above, thereby adding P1 number of parity data bytes ineach column. Finally, the primary encoder 410 performs CRC-encoding oneach row, thereby adding a 2-byte checksum in each row.

FIG. 32( b) illustrates an example of the RS-CRC encoder 422 of thesecondary encoder 420 receiving mobile service data packets of thesecondary ensemble that are to be assigned to regions C/D within thecorresponding data group, so as to create an RS frame having the size ofN2(row)×187(column). Then, in this example, the secondary encoder 420performs RS-encoding on each column of the RS frame created as describedabove, thereby adding P2 number of parity data bytes in each column.Finally, the secondary encoder 420 performs CRC-encoding on each row,thereby adding a 2-byte checksum in each row.

At this point, each of the RS-CRC encoders 412 and 422 may refer to apre-determined transmission parameter provided by the controller 201and/or a transmission parameter provided from external such as theservice multiplexer 100, the RS-CRC encoders 412 and 422 may be informedof RS frame information (including RS frame mode information), RSencoding information (including RS code mode), SCCC information(including SCCC block mode information and SCCC outer code modeinformation), data group information, and region information within adata group. The RS-CRC encoders 412 and 422 may refer to thetransmission parameters for the purpose of RS frame configuration, errorcorrection encoding, error detection encoding. Furthermore, thetransmission parameters should also be transmitted to the receivingsystem so that the receiving system can perform a normal decodingprocess. At this point, as an example of the present invention, thetransmission parameter is transmitted through transmission parameterchannel (TPC) to a receiving system. The TPC will be described in detailin a later.

The data of the primary RS frame, which is encoded by RS frame units androw-permuted by super frame units from the RS-CRC encoder 412 of theprimary encoder 410, are outputted to the RS frame divider 413. If thesecondary encoder 420 also operates in the embodiment of the presentinvention, the data of the secondary RS frame, which is encoded by RSframe units and row-permuted by super frame units from the RS-CRCencoder 422 of the secondary encoder 420, are outputted to the RS framedivider 423. The RS frame divider 413 of the primary encoder 410 dividesthe primary RS frame into several portions, which are then outputted tothe output multiplexer (MUX) 320. Each portion of the primary RS frameis equivalent to a data amount that can be transmitted by one datagroup. Similarly, the RS frame divider 423 of the secondary encoder 420divides the secondary RS frame into several portions, which are thenoutputted to the output multiplexer (MUX) 320.

Hereinafter, the RS frame divider 413 of the primary RS encoder 410 willnow be described in detail. Also, in order to simplify the descriptionof the present invention, it is assumed that an RS frame having the sizeof N(row)×187(column), as shown in FIG. 30( a) to FIG. 30( c), that Pnumber of parity data bytes are added to each column by RS-encoding theRS frame, and that a 2-byte checksum is added to each row byCRC-encoding the RS frame. Accordingly, the RS frame divider 413 divides(or partitions) the encoded RS frame having the size of(N+2)(row)×187(column) into several portions, each having the size of PL(wherein PL corresponds to the length of the RS frame portion).

At this point, as shown in Table 2 to Table 5, the value of PL may varydepending upon the RS frame mode, SCCC block mode, and SCCC outer codermode. Also, the total number of data bytes of the RS-encoded andCRC-encoded RS frame is equal to or smaller than 5×NoG×PL . In thiscase, the RS frame is divided (or partitioned) into ((5×NoG)−1) numberof portions each having the size of PL and one portion having a sizeequal to smaller than PL. More specifically, with the exception of thelast portion of the RS frame, each of the remaining portions of the RSframe has an equal size of PL. If the size of the last portion issmaller than PL, a stuffing byte (or dummy byte) may be inserted inorder to fill (or replace) the lacking number of data bytes, therebyenabling the last portion of the RS frame to also be equal to PL. Eachportion of an RS frame corresponds to the amount of data that are to beSCCC-encoded and mapped into a single data group of a parade.

FIG. 33( a) and FIG. 33( b) respectively illustrate examples of adding Snumber of stuffing bytes, when an RS frame having the size of(N+2)(row)×(187+P)(column) is divided into 5×NoG number of portions,each having the size of PL. More specifically, the RS-encoded andCRC-encoded RS frame, shown in FIG. 33( a), is divided into severalportions, as shown in FIG. 33( b). The number of divided portions at theRS frame is equal to (5×NoG). Particularly, the first ((5×NoG)−1) numberof portions each has the size of PL, and the last portion of the RSframe may be equal to or smaller than PL. If the size of the lastportion is smaller than PL, a stuffing byte (or dummy byte) may beinserted in order to fill (or replace) the lacking number of data bytes,as shown in Equation 6 below, thereby enabling the last portion of theRS frame to also be equal to PL.

S=(5×NoG×PL)−((N+2)×(187+P))   Equation 6

Herein, each portion including data having the size of PL passes throughthe output multiplexer 320 of the MH frame encoder 301, which is thenoutputted to the block processor 302.

At this point, the mapping order of the RS frame portions to a parade ofdata groups in not identical with the group assignment order defined inEquation 1. When given the group positions of a parade in an MH frame,the SCCC-encoded RS frame portions will be mapped in a time order (i.e.,in a left-to-right direction).

For example, as shown in FIG. 11, data groups of the 2^(nd) parade(Parade #1) are first assigned (or allocated) to the 13^(th) slot (Slot#12) and then assigned to the 3^(rd) slot (Slot #2). However, when thedata are actually placed in the assigned slots, the data are placed in atime sequence (or time order, i.e., in a left-to-right direction). Morespecifically, the 1st data group of Parade #1 is placed in Slot #2, andthe 2^(nd) data group of Parade #1 is placed in Slot #12.

Block Processor

Meanwhile, the block processor 302 performs an SCCC outer encodingprocess on the output of the MH frame encoder 301. More specifically,the block processor 302 receives the data of each error correctionencoded portion. Then, the block processor 302 encodes the data onceagain at a coding rate of 1/H (wherein H is an integer equal to orgreater than 2 (i.e., H≧2)), thereby outputting the 1/H-rate encodeddata to the group formatter 303. According to the embodiment of thepresent invention, the input data are encoded either at a coding rate of½ (also referred to as “½-rate encoding”) or at a coding rate of ¼ (alsoreferred to as “¼-rate encoding”). The data of each portion outputtedfrom the MH frame encoder 301 may include at least one of pure mobileservice data, RS parity data, CRC data, and stuffing data. However, in abroader meaning, the data included in each portion may correspond todata for mobile services. Therefore, the data included in each portionwill all be considered as mobile service data and described accordingly.

The group formatter 303 inserts the mobile service dataSCCC-outer-encoded and outputted from the block processor 302 in thecorresponding region within the data group, which is formed inaccordance with a pre-defined rule. Also, in association with the datadeinterleaving process, the group formatter 303 inserts various placeholders (or known data place holders) in the corresponding region withinthe data group. Thereafter, the group formatter 303 deinterleaves thedata within the data group and the place holders.

According to the present invention, with reference to data after beingdata-interleaved, as shown in FIG. 5, a data groups is configured of 10MH blocks (B1 to B10) and divided into 4 regions (A, B, C, and D). Also,as shown in FIG. 5, when it is assumed that the data group is dividedinto a plurality of hierarchical regions, as described above, the blockprocessor 302 may encode the mobile service data, which are to beinserted to each region based upon the characteristic of eachhierarchical region, at different coding rates. For example, the blockprocessor 302 may encode the mobile service data, which are to beinserted in region A/B within the corresponding data group, at a codingrate of ½. Then, the group formatter 303 may insert the ½-rate encodedmobile service data to region A/B. Also, the block processor 302 mayencode the mobile service data, which are to be inserted in region C/Dwithin the corresponding data group, at a coding rate of ¼ having higher(or stronger) error correction ability than the ½-coding rate.Thereafter, the group formatter 303 may insert the ½-rate encoded mobileservice data to region C/D. In another example, the block processor 302may encode the mobile service data, which are to be inserted in regionC/D, at a coding rate having higher error correction ability than the¼-coding rate. Then, the group formatter 303 may either insert theencoded mobile service data to region C/D, as described above, or leavethe data in a reserved region for future usage.

According to another embodiment of the present invention, the blockprocessor 302 may perform a 1/H-rate encoding process in SCCC blockunits. Herein, the SCCC block includes at least one MH block. At thispoint, when 1/H-rate encoding is performed in MH block units, the MHblocks (B1 to B10) and the SCCC block (SCB1 to SCB10) become identicalto one another (i.e., SCB1=B1, SCB2=B2, SCB3=B3, SCB4=B4, SCB5=B5,SCB6=B6, SCB7=B7, SCB8=B8, SCB9=B9, and SCB10=B10). For example, the MHblock 1 (B1) may be encoded at the coding rate of ½, the MH block 2 (B2)may be encoded at the coding rate of ¼, and the MH block 3 (B3) may beencoded at the coding rate of ½. The coding rates are appliedrespectively to the remaining MH blocks.

Alternatively, a plurality of MH blocks within regions A, B, C, and Dmay be grouped into one SCCC block, thereby being encoded at a codingrate of 1/H in SCCC block units. Accordingly, the receiving performanceof region C/D may be enhanced. For example, MH block 1 (B1) to MH block5 (B5) may be grouped into one SCCC block and then encoded at a codingrate of ½. Thereafter, the group formatter 303 may insert the ½-rateencoded mobile service data to a section starting from MH block 1 (B1)to MH block 5 (B5). Furthermore, MH block 6 (B6) to MH block 10 (B10)may be grouped into one SCCC block and then encoded at a coding rate of¼. Thereafter, the group formatter 303 may insert the ¼-rate encodedmobile service data to another section starting from MH block 6 (B6) toMH block 10 (B10). In this case, one data group may consist of two SCCCblocks.

According to another embodiment of the present invention, one SCCC blockmay be formed by grouping two MH blocks. For example, MH block 1 (B1)and MH block 6 (B6) may be grouped into one SCCC block (SCB1).Similarly, MH block 2 (B2) and MH block 7 (B7) may be grouped intoanother SCCC block (SCB2). Also, MH block 3 (B3) and MH block 8 (B8) maybe grouped into another SCCC block (SCB3). And, MH block 4 (B4) and MHblock 9 (B9) may be grouped into another SCCC block (SCB4). Furthermore,MH block 5 (B5) and MH block 10 (B10) may be grouped into another SCCCblock (SCB5). In the above-described example, the data group may consistof 10 MH blocks and 5 SCCC blocks. Accordingly, in a data (or signal)receiving environment undergoing frequent and severe channel changes,the receiving performance of regions C and D, which is relatively moredeteriorated than the receiving performance of region A, may bereinforced. Furthermore, since the number of mobile service data symbolsincreases more and more from region A to region D, the error correctionencoding performance becomes more and more deteriorated. Therefore, whengrouping a plurality of MH block to form one SCCC block, suchdeterioration in the error correction encoding performance may bereduced.

As described-above, when the block processor 302 performs encoding at a1/H-coding rate, information associated with SCCC should be transmittedto the receiving system in order to accurately recover the mobileservice data. Table 7 below shows an example of a SCCC block mode, whichindicating the relation between an MH block and an SCCC block, amongdiverse SCCC block information.

TABLE 7 SCCC Block Mode 00 01 10 11 Description One MH Block Two MHBlocks per SCCC Block per SCCC Block SCB input, SCB input, SCB MH BlockMH Blocks Reserved Reserved SCB1 B1 B1 + B6 SCB2 B2 B2 + B7 SCB3 B3 B3 +B8 SCB4 B4 B4 + B9 SCB5 B5 B5 + B10 SCB6 B6 — SCB7 B7 — SCB8 B8 — SCB9B9 — SCB10 B10 —

More specifically, Table 4 shows an example of 2 bits being allocated inorder to indicate the SCCC block mode. For example, when the SCCC blockmode value is equal to ‘00’, this indicates that the SCCC block and theMH block are identical to one another. Also, when the SCCC block modevalue is equal to ‘01’, this indicates that each SCCC block isconfigured of 2 MH blocks.

As described above, if one data group is configured of 2 SCCC blocks,although it is not indicated in Table 7, this information may also beindicated as the SCCC block mode. For example, when the SCCC block modevalue is equal to ‘10’, this indicates that each SCCC block isconfigured of 5 MH blocks and that one data group is configured of 2SCCC blocks. Herein, the number of MH blocks included in an SCCC blockand the position of each MH block may vary depending upon the settingsmade by the system designer. Therefore, the present invention will notbe limited to the examples given herein. Accordingly, the SCCC modeinformation may also be expanded.

An example of a coding rate information of the SCCC block, i.e., SCCCouter code mode, is shown in Table 8 below.

TABLE 8 SCCC outer code mode (2 bits) Description 00 Outer code rate ofSCCC block is ½ rate 01 Outer code rate of SCCC block is ¼ rate 10Reserved 11 Reserved

More specifically, Table 8 shows an example of 2 bits being allocated inorder to indicate the coding rate information of the SCCC block. Forexample, when the SCCC outer code mode value is equal to ‘00’, thisindicates that the coding rate of the corresponding SCCC block is ½.And, when the SCCC outer code mode value is equal to ‘01’, thisindicates that the coding rate of the corresponding SCCC block is ¼.

If the SCCC block mode value of Table 7 indicates ‘00’, the SCCC outercode mode may indicate the coding rate of each MH block with respect toeach MH block. In this case, since it is assumed that one data groupincludes 10 MH blocks and that 2 bits are allocated for each SCCC blockmode, a total of 20 bits are required for indicating the SCCC blockmodes of the 10 MH modes. In another example, when the SCCC block modevalue of Table 7 indicates ‘00’, the SCCC outer code mode may indicatethe coding rate of each region with respect to each region within thedata group. In this case, since it is assumed that one data groupincludes 4 regions (i.e., regions A, B, C, and D) and that 2 bits areallocated for each SCCC block mode, a total of 8 bits are required forindicating the SCCC block modes of the 4 regions. In another example,when the SCCC block mode value of Table 7 is equal to ‘01’, each of theregions A, B, C, and D within the data group has the same SCCC outercode mode.

Meanwhile, an example of an SCCC output block length (SOBL) for eachSCCC block, when the SCCC block mode value is equal to ‘00’, is shown inTable 9 below.

TABLE 9 SIBL SCCC Block SOBL ½ rate ¼ rate SCB1 (B1) 528 264 132 SCB2(B2) 1536 768 384 SCB3 (B3) 2376 1188 594 SCB4 (B4) 2388 1194 597 SCB5(B5) 2772 1386 693 SCB6 (B6) 2472 1236 618 SCB7 (B7) 2772 1386 693 SCB8(B8) 2508 1254 627 SCB9 (B9) 1416 708 354 SCB10 (B10) 480 240 120

More specifically, when given the SCCC output block length (SOBL) foreach SCCC block, an SCCC input block length (SIBL) for eachcorresponding SCCC block may be decided based upon the outer coding rateof each SCCC block. The SOBL is equivalent to the number of SCCC output(or outer-encoded) bytes for each SCCC block. And, the SIBL isequivalent to the number of SCCC input (or payload) bytes for each SCCCblock. Table 10 below shows an example of the SOBL and SIBL for eachSCCC block, when the SCCC block mode value is equal to ‘01’.

TABLE 10 SIBL ½ ¼ SCCC Block SOBL rate rate SCB1 (B1 + B6) 528 264 132SCB2 (B2 + B7) 1536 768 384 SCB3 (B3 + B8) 2376 1188 594 SCB4 (B4 + B9)2388 1194 597 SCB5 (B5 + B10) 2772 1386 693

In order to do so, as shown in FIG. 34, the block processor 302 includesa RS frame portion-SCCC block converter 511, a byte-bit converter 512, aconvolution encoder 513, a symbol interleaver 514, a symbol-byteconverter 515, and an SCCC block-MH block converter 516. Theconvolutional encoder 513 and the symbol interleaver 514 are virtuallyconcatenated with the trellis encoding module in the post-processor inorder to configure an SCCC block. More specifically, the RS frameportion-SCCC block converter 511 divides the RS frame portions, whichare being inputted, into multiple SCCC blocks using the SIBL of Table 9and Table 10 based upon the RS code mode, SCCC block mode, and SCCCouter code mode. Herein, the MH frame encoder 301 may output onlyprimary RS frame portions or both primary RS frame portions andsecondary RS frame portions in accordance with the RS frame mode.

When the RS Frame mode is set to ‘00’, a portion of the primary RS Frameequal to the amount of data, which are to be SCCC outer encoded andmapped to 10 MH blocks (B1 to B10) of a data group, will be provided tothe block processor 302. When the SCCC block mode value is equal to‘00’, then the primary RS frame portion will be split into 10 SCCCBlocks according to Table 9. Alternatively, when the SCCC block modevalue is equal to ‘01’, then the primary RS frame will be split into 5SCCC blocks according to Table 10.

When the RS frame mode value is equal to ‘01’, then the block processor302 may receive two RS frame portions. The RS frame mode value of ‘01’will not be used with the SCCC block mode value of ‘01’. The firstportion from the primary RS frame will be SCCC-outer-encoded as SCCCBlocks SCB3, SCB4, SCB5, SCB6, SCB7, and SCB8 by the block processor302. The SCCC Blocks SCB3 and SCB8 will be mapped to region B and theSCCC blocks SCB4, SCB5, SCB6, and SCB7 shall be mapped to region A bythe group formatter 303. The second portion from the secondary RS framewill also be SCCC-outer-encoded, as SCB1, SCB2, SCB9, and SCB10, by theblock processor 302. The group formatter 303 will map the SCCC blocksSCB1 and SCB10 to region D as the MH blocks B1 and B10, respectively.Similarly, the SCCC blocks SCB2 and SCB9 will be mapped to region C asthe MH blocks B2 and B9.

The byte-bit converter 512 identifies the mobile service data bytes ofeach SCCC block outputted from the RS frame portion-SCCC block converter511 as data bits, which are then outputted to the convolution encoder513. The convolution encoder 513 performs one of ½-rate encoding and¼-rate encoding on the inputted mobile service data bits.

FIG. 35 illustrates a detailed block diagram of the convolution encoder513. The convolution encoder 513 includes two delay units 521 and 523and three adders 522, 524, and 525. Herein, the convolution encoder 513encodes an input data bit U and outputs the coded bit U to 5 bits (u0 tou4). At this point, the input data bit U is directly outputted asuppermost bit u0 and simultaneously encoded as lower bit u1u2u3u4 andthen outputted. More specifically, the input data bit U is directlyoutputted as the uppermost bit u0 and simultaneously outputted to thefirst and third adders 522 and 525.

The first adder 522 adds the input data bit U and the output bit of thefirst delay unit 521 and, then, outputs the added bit to the seconddelay unit 523. Then, the data bit delayed by a pre-determined time(e.g., by 1 clock) in the second delay unit 523 is outputted as a lowerbit u1 and simultaneously fed-back to the first delay unit 521. Thefirst delay unit 521 delays the data bit fed-back from the second delayunit 523 by a pre-determined time (e.g., by 1 clock). Then, the firstdelay unit 521 outputs the delayed data bit as a lower bit u2 and, atthe same time, outputs the fed-back data to the first adder 522 and thesecond adder 524. The second adder 524 adds the data bits outputted fromthe first and second delay units 521 and 523 and outputs the added databits as a lower bit u3. The third adder 525 adds the input data bit Uand the output of the second delay unit 523 and outputs the added databit as a lower bit u4.

At this point, the first and second delay units 521 and 523 are reset to‘0’, at the starting point of each SCCC block. The convolution encoder513 of FIG. 35 may be used as a ½-rate encoder or a ¼-rate encoder. Morespecifically, when a portion of the output bit of the convolutionencoder 513, shown in FIG. 35, is selected and outputted, theconvolution encoder 513 may be used as one of a ½-rate encoder and a¼-rate encoder. Table 11 below shown an example of output symbols of theconvolution encoder 513.

TABLE 11 ¼ rate SCCC block SCCC block mode = Region ½ rate mode = ‘00’‘01’ A, B (u0, u1) (u0, u2), (u1, u3) (u0, u2), (u1, C, D (u0, u1), (u3,u4) u4)

For example, at the ½-coding rate, 1 output symbol (i.e., u0 and u1bits) may be selected and outputted. And, at the ¼-coding rate,depending upon the SCCC block mode, 2 output symbols (i.e., 4 bits) maybe selected and outputted. For example, when the SCCC block mode valueis equal to ‘01’, and when an output symbol configured of u0 and u2 andanother output symbol configured of u1 and u4 are selected andoutputted, a ¼-rate coding result may be obtained.

The mobile service data encoded at the coding rate of ½ or ¼ by theconvolution encoder 513 are outputted to the symbol interleaver 514. Thesymbol interleaver 514 performs block interleaving, in symbol units, onthe output data symbol of the convolution encoder 513. Morespecifically, the symbol interleaver 514 is a type of block interleaver.Any interleaver performing structural rearrangement (or realignment) maybe applied as the symbol interleaver 514 of the block processor.However, in the present invention, a variable length symbol interleaverthat can be applied even when a plurality of lengths is provided for thesymbol, so that its order may be rearranged, may also be used.

FIG. 36 illustrates a symbol interleaver according to an embodiment ofthe present invention. Particularly, FIG. 36 illustrates an example ofthe symbol interleaver when B=2112 and L=4096. Herein, B indicates ablock length in symbols that are outputted for symbol interleaving fromthe convolution encoder 513. And, L represents a block length in symbolsthat are actually interleaved by the symbol interleaver 514. At thispoint, the block length in symbols B inputted to the symbol interleaver514 is equivalent to 4×SOBL . More specifically, since one symbol isconfigured of 2 bits, the value of B may be set to be equal to 4×SOBL.

In the present invention, when performing the symbol-intereleavingprocess, the conditions of L=2^(m) (wherein m is an integer) and of L≧Bshould be satisfied. If there is a difference in value between B and L,(L-B) number of null (or dummy) symbols is added, thereby creating aninterleaving pattern, as shown in P′ (i) of FIG. 36. Therefore, Bbecomes a block size of the actual symbols that are inputted to thesymbol interleaver 514 in order to be interleaved. L becomes aninterleaving unit when the interleaving process is performed by aninterleaving pattern created from the symbol interleaver 514.

Equation 7 shown below describes the process of sequentially receiving Bnumber of symbols, the order of which is to be rearranged, and obtainingan L value satisfying the conditions of L=2^(m) (wherein m is aninteger) and of L≧B , thereby creating the interleaving so as to realign(or rearrange) the symbol order.

In relation to all places, wherein 0≦i≦B−1,

P′(i)={89×i×(i+1)/2} mod L   Equation 7

Herein, L≧B, L=2^(m), wherein m is an integer.

As shown in P′ (i) of FIG. 36, the order of B number of input symbolsand (L-B) number of null symbols is rearranged by using theabove-mentioned Equation 7. Then, as shown in P(i) of FIG. 36, the nullbyte places are removed, so as to rearrange the order. Starting with thelowest value of i, the P(i) are shifted to the left in order to fill theempty entry locations. Thereafter, the symbols of the alignedinterleaving pattern P(i) are outputted to the symbol-byte converter 515in order. Herein, the symbol-byte converter 515 converts to bytes themobile service data symbols, having the rearranging of the symbol ordercompleted and then outputted in accordance with the rearranged order,and thereafter outputs the converted bytes to the SCCC block-MH blockconverter 516. The SCCC block-MH block converter 516 converts thesymbol-interleaved SCCC blocks to MH blocks, which are then outputted tothe group formatter 303.

If the SCCC block mode value is equal to ‘00’, the SCCC block is mappedat a one-to-one (1:1) correspondence with each MH block within the datagroup. In another example, if the SCCC block mode value is equal to‘01’, each SCCC block is mapped with two MH blocks within the datagroup. For example, the SCCC block SCB1 is mapped with (B1, B6), theSCCC block SCB2 is mapped with (B2, B7), the SCCC block SCB3 is mappedwith (B3, B8), the SCCC block SCB4 is mapped with (B4, B9), and the SCCCblock SCB5 is mapped with (B5, B10). The MH block that is outputted fromthe SCCC block-MH block converter 516 is configured of mobile servicedata and FEC redundancy. In the present invention, the mobile servicedata as well as the FEC redundancy of the MH block will be collectivelyconsidered as mobile service data.

Group Formatter

The group formatter 303 inserts data of MH blocks outputted from theblock processor 302 to the corresponding MH blocks within the datagroup, which is formed in accordance with a pre-defined rule. Also, inassociation with the data-deinterleaving process, the group formatter303 inserts various place holders (or known data place holders) in thecorresponding region within the data group. More specifically, apartfrom the encoded mobile service data outputted from the block processor302, the group formatter 303 also inserts MPEG header place holders,non-systematic RS parity place holders, main service data place holders,which are associated with the data deinterleaving in a later process, asshown in FIG. 5.

Herein, the main service data place holders are inserted because themobile service data bytes and the main service data bytes arealternately mixed with one another in regions B to D based upon theinput of the data deinterleaver, as shown in FIG. 5. For example, basedupon the data outputted after data deinterleaving, the place holder forthe MPEG header may be allocated at the very beginning of each packet.Also, in order to configure an intended group format, dummy bytes mayalso be inserted. Furthermore, the group formatter 303 inserts placeholders for initializing the trellis encoding module 256 in thecorresponding regions. For example, the initialization data placeholders may be inserted in the beginning of the known data sequence.Additionally, the group formatter 303 may also insert signalinginformation, which are encoded and outputted from the signaling encoder304, in corresponding regions within the data group. At this point,reference may be made to the signaling information when the groupformatter 303 inserts each data type and respective place holders in thedata group. The process of encoding the signaling information andinserting the encoded signaling information to the data group will bedescribed in detail in a later process.

After inserting each data type and respective place holders in the datagroup, the group formatter 303 may deinterleave the data and respectiveplace holders, which have been inserted in the data group, as an inverseprocess of the data interleaver, thereby outputting the deinterleaveddata and respective place holders to the packet formatter 305. Morespecifically, when the data and respective place holders within the datagroup, which is configured (or structured) as shown in FIG. 5, aredeinterleaved by the group formatter 303 and outputted to the packetformatter 305, the structure of the data group may be identical to thestructure shown in FIG. 7. In order to do so, the group formatter 303may include a group format organizer 527, and a data deinterleaver 529,as shown in FIG. 37. The group format organizer 527 inserts data andrespective place holders in the corresponding regions within the datagroup, as described above. And, the data deinterleaver 529 deinterleavesthe inserted data and respective place holders as an inverse process ofthe data interleaver.

The packet formatter 305 removes the main service data place holders andthe RS parity place holders that were allocated for the deinterleavingprocess from the deinterleaved data being inputted. Then, the packetformatter 305 groups the remaining portion and inserts the 3-byte MPEGheader place holder in an MPEG header having a null packet PID (or anunused PID from the main service data packet). Furthermore, the packetformatter 305 adds a synchronization data byte at the beginning of each187-byte data packet. Also, when the group formatter 303 inserts knowndata place holders, the packet formatter 303 may insert actual knowndata in the known data place holders, or may directly output the knowndata place holders without any modification in order to make replacementinsertion in a later process. Thereafter, the packet formatter 305identifies the data within the packet-formatted data group, as describedabove, as a 188-byte unit mobile service data packet (i.e., MPEG TSpacket), which is then provided to the packet multiplexer 240.

Based upon the control of the controller 201, the packet multiplexer 240multiplexes the data group packet-formatted and outputted from thepacket formatter 306 and the main service data packet outputted from thepacket jitter mitigator 220. Then, the packet multiplexer 240 outputsthe multiplexed data packets to the data randomizer 251 of thepost-processor 250. More specifically, the controller 201 controls thetime-multiplexing of the packet multiplexer 240. If the packetmultiplexer 240 receives 118 mobile service data packets from the packetformatter 305, 37 mobile service data packets are placed before a placefor inserting VSB field synchronization. Then, the remaining 81 mobileservice data packets are placed after the place for inserting VSB fieldsynchronization. The multiplexing method may be adjusted by diversevariables of the system design. The multiplexing method and multiplexingrule of the packet multiplexer 240 will be described in more detail in alater process.

Also, since a data group including mobile service data in-between thedata bytes of the main service data is multiplexed (or allocated) duringthe packet multiplexing process, the shifting of the chronologicalposition (or place) of the main service data packet becomes relative.Also, a system object decoder (i.e., MPEG decoder) for processing themain service data of the receiving system, receives and decodes only themain service data and recognizes the mobile service data packet as anull data packet.

Therefore, when the system object decoder of the receiving systemreceives a main service data packet that is multiplexed with the datagroup, a packet jitter occurs.

At this point, since a multiple-level buffer for the video data existsin the system object decoder and the size of the buffer is relativelylarge, the packet jitter generated from the packet multiplexer 240 doesnot cause any serious problem in case of the video data. However, sincethe size of the buffer for the audio data in the object decoder isrelatively small, the packet jitter may cause considerable problem. Morespecifically, due to the packet jitter, an overflow or underflow mayoccur in the buffer for the main service data of the receiving system(e.g., the buffer for the audio data). Therefore, the packet jittermitigator 220 re-adjusts the relative position of the main service datapacket so that the overflow or underflow does not occur in the systemobject decoder.

In the present invention, examples of repositioning places for the audiodata packets within the main service data in order to minimize theinfluence on the operations of the audio buffer will be described indetail. The packet jitter mitigator 220 repositions the audio datapackets in the main service data section so that the audio data packetsof the main service data can be as equally and uniformly aligned andpositioned as possible. Additionally, when the positions of the mainservice data packets are relatively re-adjusted, associated programclock reference (PCR) values may also be modified accordingly. The PCRvalue corresponds to a time reference value for synchronizing the timeof the MPEG decoder. Herein, the PCR value is inserted in a specificregion of a TS packet and then transmitted.

In the example of the present invention, the packet jitter mitigator 220also performs the operation of modifying the PCR value. The output ofthe packet jitter mitigator 220 is inputted to the packet multiplexer240. As described above, the packet multiplexer 240 multiplexes the mainservice data packet outputted from the packet jitter mitigator 220 withthe mobile service data packet outputted from the pre-processor 230 intoa burst structure in accordance with a pre-determined multiplexing rule.Then, the packet multiplexer 240 outputs the multiplexed data packets tothe data randomizer 251 of the post-processor 250.

If the inputted data correspond to the main service data packet, thedata randomizer 251 performs the same randomizing process as that of theconventional randomizer. More specifically, the synchronization bytewithin the main service data packet is deleted. Then, the remaining 187data bytes are randomized by using a pseudo random byte generated fromthe data randomizer 251. Thereafter, the randomized data are outputtedto the RS encoder/non-systematic RS encoder 252.

On the other hand, if the inputted data correspond to the mobile servicedata packet, the data randomizer 251 may randomize only a portion of thedata packet. For example, if it is assumed that a randomizing processhas already been performed in advance on the mobile service data packetby the pre-processor 230, the data randomizer 251 deletes thesynchronization byte from the 4-byte MPEG header included in the mobileservice data packet and, then, performs the randomizing process only onthe remaining 3 data bytes of the MPEG header. Thereafter, therandomized data bytes are outputted to the RS encoder/non-systematic RSencoder 252. More specifically, the randomizing process is not performedon the remaining portion of the mobile service data excluding the MPEGheader. In other words, the remaining portion of the mobile service datapacket is directly outputted to the RS encoder/non-systematic RS encoder252 without being randomized. Also, the data randomizer 251 may or maynot perform a randomizing process on the known data (or known data placeholders) and the initialization data place holders included in themobile service data packet.

The RS encoder/non-systematic RS encoder 252 performs an RS encodingprocess on the data being randomized by the data randomizer 251 or onthe data bypassing the data randomizer 251, so as to add 20 bytes of RSparity data. Thereafter, the processed data are outputted to the datainterleaver 253. Herein, if the inputted data correspond to the mainservice data packet, the RS encoder/non-systematic RS encoder 252performs the same systematic RS encoding process as that of theconventional broadcasting system, thereby adding the 20-byte RS paritydata at the end of the 187-byte data. Alternatively, if the inputteddata correspond to the mobile service data packet, the RSencoder/non-systematic RS encoder 252 performs a non-systematic RSencoding process. At this point, the 20-byte RS parity data obtainedfrom the non-systematic RS encoding process are inserted in apre-decided parity byte place within the mobile service data packet.

The data interleaver 253 corresponds to a byte unit convolutionalinterleaver. The output of the data interleaver 253 is inputted to theparity replacer 254 and to the non-systematic RS encoder 255. Meanwhile,a process of initializing a memory within the trellis encoding module256 is primarily required in order to decide the output data of thetrellis encoding module 256, which is located after the parity replacer254, as the known data pre-defined according to an agreement between thereceiving system and the transmitting system. More specifically, thememory of the trellis encoding module 256 should first be initializedbefore the received known data sequence is trellis-encoded. At thispoint, the beginning portion of the known data sequence that is receivedcorresponds to the initialization data place holder and not to theactual known data. Herein, the initialization data place holder has beenincluded in the data by the group formatter within the pre-processor 230in an earlier process. Therefore, the process of generatinginitialization data and replacing the initialization data place holderof the corresponding memory with the generated initialization data arerequired to be performed immediately before the inputted known datasequence is trellis-encoded.

Additionally, a value of the trellis memory initialization data isdecided and generated based upon a memory status of the trellis encodingmodule 256. Further, due to the newly replaced initialization data, aprocess of newly calculating the RS parity and replacing the RS parity,which is outputted from the data interleaver 253, with the newlycalculated RS parity is required. Therefore, the non-systematic RSencoder 255 receives the mobile service data packet including theinitialization data place holders, which are to be replaced with theactual initialization data, from the data interleaver 253 and alsoreceives the initialization data from the trellis encoding module 256.

Among the inputted mobile service data packet, the initialization dataplace holders are replaced with the initialization data, and the RSparity data that are added to the mobile service data packet are removedand processed with non-systematic RS encoding. Thereafter, the new RSparity obtained by performing the non-systematic RS encoding process isoutputted to the parity replacer 255. Accordingly, the parity replacer255 selects the output of the data interleaver 253 as the data withinthe mobile service data packet, and the parity replacer 255 selects theoutput of the non-systematic RS encoder 255 as the RS parity. Theselected data are then outputted to the trellis encoding module 256.

Meanwhile, if the main service data packet is inputted or if the mobileservice data packet, which does not include any initialization dataplace holders that are to be replaced, is inputted, the parity replacer254 selects the data and RS parity that are outputted from the datainterleaver 253. Then, the parity replacer 254 directly outputs theselected data to the trellis encoding module 256 without anymodification. The trellis encoding module 256 converts the byte-unitdata to symbol units and performs a 12-way interleaving process so as totrellis-encode the received data. Thereafter, the processed data areoutputted to the synchronization multiplexer 260.

FIG. 38 illustrates a detailed diagram of one of 12 trellis encodersincluded in the trellis encoding module 256. Herein, the trellis encoderincludes first and second multiplexers 531 and 541, first and secondadders 532 and 542, and first to third memories 533, 542, and 544. Morespecifically, the first to third memories 533, 542, and 544 areinitialized by a set of trellis initialization data inserted in aninitialization data place holder by the parity replacer 254 and, then,outputted. More specifically, when the first two 2-bit symbols, whichare converted from each trellis initialization data byte, are inputted,the input bits of the trellis encoder will be replaced by the memoryvalues of the trellis encoder, as shown in FIG. 38.

Since 2 symbols (i.e., 4 bits) are required for trellis initialization,the last 2 symbols (i.e., 4 bits) from the trellis initialization bytesare not used for trellis initialization and are considered as a symbolfrom a known data byte and processed accordingly. When the trellisencoder is in the initialization mode, the input comes from an internaltrellis status (or state) and not from the parity replacer 254. When thetrellis encoder is in the normal mode, the input symbol provided fromthe parity replacer 254 will be processed. The trellis encoder providesthe converted (or modified) input data for trellis initialization to thenon-systematic RS encoder 255.

More specifically, when a selection signal designates a normal mode, thefirst multiplexer 531 selects an upper bit X2 of the input symbol. And,when a selection signal designates an initialization mode, the firstmultiplexer 531 selects the output of the first memory 533 and outputsthe selected output data to the first adder 532. The first adder 532adds the output of the first multiplexer 531 and the output of the firstmemory 533, thereby outputting the added result to the first memory 533and, at the same time, as a most significant (or uppermost) bit Z2. Thefirst memory 533 delays the output data of the first adder 532 by 1clock, thereby outputting the delayed data to the first multiplexer 531and the first adder 532.

Meanwhile, when a selection signal designates a normal mode, the secondmultiplexer 541 selects a lower bit X1 of the input symbol. And, when aselection signal designates an initialization mode, the secondmultiplexer 541 selects the output of the second memory 542, therebyoutputting the selected result to the second adder 543 and, at the sametime, as a lower bit Z1. The second adder 543 adds the output of thesecond multiplexer 541 and the output of the second memory 542, therebyoutputting the added result to the third memory 544. The third memory544 delays the output data of the second adder 543 by 1 clock, therebyoutputting the delayed data to the second memory 542 and, at the sametime, as a least significant (or lowermost) bit Z0. The second memory542 delays the output data of the third memory 544 by 1 clock, therebyoutputting the delayed data to the second adder 543 and the secondmultiplexer 541.

The synchronization multiplexer 260 inserts a field synchronizationsignal and a segment synchronization signal to the data outputted fromthe trellis encoding module 256 and, then, outputs the processed data tothe pilot inserter 271 of the transmission unit 270. Herein, the datahaving a pilot inserted therein by the pilot inserter 271 are modulatedby the modulator 272 in accordance with a pre-determined modulatingmethod (e.g., a VSB method). Thereafter, the modulated data aretransmitted to each receiving system though the radio frequency (RF)up-converter 273.

Multiplexing Method of Packet Multiplexer

Data of the error correction encoded and 1/H-rate encoded primary RSframe (i.e., when the RS frame mode value is equal to ‘00’) orprimary/secondary RS frame (i.e., when the RS frame mode value is equalto ‘01’), are divided into a plurality of data groups by the groupformatter 303. Then, the divided data portions are assigned to at leastone of regions A to D of each data group or to an MH block among the MHblocks B1 to B10, thereby being deinterleaved. Then, the deinterleaveddata group passes through the packet formatter 305, thereby beingmultiplexed with the main service data by the packet multiplexer 240based upon a de-decided multiplexing rule. The packet multiplexer 240multiplexes a plurality of consecutive data groups, so that the datagroups are assigned to be spaced as far apart from one another aspossible within the sub-frame. For example, when it is assumed that 3data groups are assigned to a sub-frame, the data groups are assigned toa 1^(st) slot (Slot #0), a 5^(th) slot (Slot #4), and a 9^(th) slot(Slot #8) in the sub-frame, respectively.

As described-above, in the assignment of the plurality of consecutivedata groups, a plurality of parades are multiplexed and outputted so asto be spaced as far apart from one another as possible within asub-frame. For example, the method of assigning data groups and themethod of assigning parades may be identically applied to all sub-framesfor each MH frame or differently applied to each MH frame.

FIG. 10 illustrates an example of a plurality of data groups included ina single parade, wherein the number of data groups included in asub-frame is equal to ‘3’, and wherein the data groups are assigned toan MH frame by the packet multiplexer 240. Referring to FIG. 10, 3 datagroups are sequentially assigned to a sub-frame at a cycle period of 4slots. Accordingly, when this process is equally performed in the 5sub-frames included in the corresponding MH frame, 15 data groups areassigned to a single MH frame. Herein, the 15 data groups correspond todata groups included in a parade.

When data groups of a parade are assigned as shown in FIG. 10, thepacket multiplexer 240 may either assign main service data to each datagroup, or assign data groups corresponding to different parades betweeneach data group. More specifically, the packet multiplexer 240 mayassign data groups corresponding to multiple parades to one MH frame.Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, the packet multiplexer240 may assign data groups included in other parades to an MH frameaccording to a cycle period of 4 slots. At this point, data groups of adifferent parade may be sequentially assigned to the respective slots ina circular method. Herein, the data groups are assigned to slotsstarting from the ones to which data groups of the previous parade havenot yet been assigned. For example, when it is assumed that data groupscorresponding to a parade are assigned as shown in FIG. 10, data groupscorresponding to the next parade may be assigned to a sub-frame startingeither from the 12^(th) slot of a sub-frame.

FIG. 11 illustrates an example of assigning and transmitting 3 parades(Parade #0, Parade #1, and Parade #2) to an MH frame. For example, whenthe 1^(st) parade (Parade #0) includes 3 data groups for each sub-frame,the packet multiplexer 240 may obtain the positions of each data groupswithin the sub-frames by substituting values ‘0’ to ‘2’ for i inEquation 1. More specifically, the data groups of the 1^(st) parade(Parade #0) are sequentially assigned to the 1^(st), 5^(th), and 9^(th)slots (Slot #0, Slot #4, and Slot #8) within the sub-frame. Also, whenthe 2^(nd) parade includes 2 data groups for each sub-frame, the packetmultiplexer 240 may obtain the positions of each data groups within thesub-frames by substituting values ‘3’ and ‘4’ for i in Equation 1. Morespecifically, the data groups of the 2^(nd) parade (Parade #1) aresequentially assigned to the 2^(nd) and 12^(th) slots (Slot #3 and Slot#11) within the sub-frame. Finally, when the 3^(rd) parade includes 2data groups for each sub-frame, the packet multiplexer 240 may obtainthe positions of each data groups within the sub-frames by substitutingvalues ‘5’ and ‘6’ for i in Equation 1. More specifically, the datagroups of the 3^(rd) parade (Parade #2) are sequentially assigned andoutputted to the 7^(th) and 11^(th) slots (Slot #6 and Slot #10) withinthe sub-frame.

As described above, the packet multiplexer 240 may multiplex and outputdata groups of multiple parades to a single MH frame, and, in eachsub-frame, the multiplexing process of the data groups may be performedserially with a group space of 4 slots from left to right. Therefore, anumber of groups of one parade per sub-frame (NOG) may correspond to anyone integer from ‘1’ to ‘8’. Herein, since one MH frame includes 5sub-frames, the total number of data groups within a parade that can beallocated to an MH frame may correspond to any one multiple of ‘5’ranging from ‘5’ to ‘40’.

Processing Signaling Information

The present invention assigns signaling information areas for insertingsignaling information to some areas within each data group. FIG. 39illustrates an example of assigning signaling information areas forinserting signaling information starting from the 1^(st) segment of the4^(th) MH block (B4) to a portion of the 2^(nd) segment. Morespecifically, 276(=207+69) bytes of the 4^(th) MH block (B4) in eachdata group are assigned as the signaling information area. In otherwords, the signaling information area consists of 207 bytes of the1^(st) segment and the first 69 bytes of the 2^(nd) segment of the4^(th) MH block (B4). For example, the 1^(st) segment of the 4^(th) MHblock (B4) corresponds to the 17^(th) or 173^(rd) segment of a VSBfield.

The signaling information that is to be inserted in the signalinginformation area is FEC-encoded by the signaling encoder 304, therebyinputted to the group formatter 303.

The group formatter 303 inserts the signaling information, which isFEC-encoded and outputted by the signaling encoder 304, in the signalinginformation area within the data group. Herein, the signalinginformation may be identified by two different types of signalingchannels: a transmission parameter channel (TPC) and a fast informationchannel (FIC). Herein, the TPC information corresponds to signalinginformation including transmission parameters, such as RSframe-associated information, SCCC-associated information, and MHframe-associated information. However, the signaling informationpresented herein is merely exemplary. And, since the adding or deletingof signaling information included in the TPC may be easily adjusted andmodified by one skilled in the art, the present invention will,therefore, not be limited to the examples set forth herein. Furthermore,the FIC is provided to enable a fast service acquisition of datareceivers, and the FIC includes cross layer information between thephysical layer and the upper layer(s).

FIG. 40 illustrates a detailed block diagram of the signaling encoder304 according to the present invention. Referring to FIG. 40, thesignaling encoder 304 includes a TPC encoder 561, an FIC encoder 562, ablock interleaver 563, a multiplexer 564, a signaling randomizer 565,and a PCCC encoder 566. The TPC encoder 561 receives 10-bytes of TPCdata and performs (18,10)-RS encoding on the 10-bytes of TPC data,thereby adding 8 bytes of parity data to the 10 bytes of TPC data. The18 bytes of RS-encoded TPC data are outputted to the multiplexer 564.The FIC encoder 562 receives 37-bytes of FIC data and performs(51,37)-RS encoding on the 37-bytes of FIC data, thereby adding 14 bytesof parity data to the 37 bytes of FIC data. Thereafter, the 51 bytes ofRS-encoded FIC data are inputted to the block interleaver 563, therebybeing interleaved in predetermined block units.

Herein, the block interleaver 563 corresponds to a variable length blockinterleaver. The block interleaver 563 interleaves the FIC data withineach sub-frame in TNoG(column)×51(row) block units and then outputs theinterleaved data to the multiplexer 564. Herein, the TNOG corresponds tothe total number of data groups being assigned to all sub-frames withinan MH frame. The block interleaver 563 is synchronized with the firstset of FIC data in each sub-frame. The block interleaver 563 writes 51bytes of incoming (or inputted) RS codewords in a row direction (i.e.,row-by-row) and left-to-right and up-to-down directions and reads 51bytes of RS codewords in a column direction (i.e., column-by-column) andleft-to-right and up-to-down directions, thereby outputting the RScodewords.

The multiplexer 564 multiplexes the RS-encoded TPC data from the TPCencoder 561 and the block-interleaved FIC data from the blockinterleaver 563 along a time axis. Then, the multiplexer 564 outputs 69bytes of the multiplexed data to the signaling randomizer 565. Thesignaling randomizer 565 randomizes the multiplexed data and outputs therandomized data to the PCCC encoder 566. The signaling randomizer 565may use the same generator polynomial of the randomizer used for mobileservice data. Also, initialization occurs in each data group. The PCCCencoder 566 corresponds to an inner encoder performing PCCC-encoding onthe randomized data (i.e., signaling information data). The PCCC encoder566 may include 6 even component encoders and 6 odd component encoders.

FIG. 41 illustrates an example of a syntax structure of TPC data beinginputted to the TPC encoder 561. The TPC data are inserted in thesignaling information area of each data group and then transmitted. TheTPC data may include a sub-frame_number field, a slot_number field, aparade_id field, a starting_group_number (SGN) field, a number_of_groups(NoG) field, a parade_repetition_cycle (PRC) field, an RS_frame_modefield, an RS_code_mode_primary field, an RS_code_mode_secondary field,an SCCC_block_mode field, an SCCC_outer_code_mode_A field, anSCCC_outer_code_mode_B feld, an SCCC_outer_code_mode_C field, anSCCC_outer_code_mode_D field, an FIC_version field, aparade_continuity_counter field, and a TNOG field.

The Sub-Frame_number field corresponds to the current Sub-Frame numberwithin the MH frame, which is transmitted for MH frame synchronization.The value of the Sub-Frame_number field may range from 0 to 4. TheSlot_number field indicates the current slot number within thesub-frame, which is transmitted for MH frame synchronization. Also, thevalue of the Sub-Frame_number field may range from 0 to 15. TheParade_id field identifies the parade to which this group belongs. Thevalue of this field may be any 7-bit value. Each parade in a MHtransmission shall have a unique Parade_id field.

Communication of the Parade_id between the physical layer and themanagement layer may be performed by means of an Ensemble_id fieldformed by adding one bit to the left of the Parade_id field. If theEnsemble_id field is used for the primary Ensemble delivered throughthis parade, the added MSB shall be equal to ‘0’. Otherwise, if theEnsemble_id field is used for the secondary ensemble, the added MSBshall be equal to ‘1’. Assignment of the Parade_id field values mayoccur at a convenient level of the system, usually in the managementlayer. The starting_group_number (SGN) field shall be the firstSlot_number for a parade to which this group belongs, as determined byEquation 1 (i.e., after the Slot numbers for all preceding parades havebeen calculated). The SGN and NoG shall be used according to Equation 1to obtain the slot numbers to be allocated to a parade within thesub-frame.

The number_of_Groups (NoG) field shall be the number of groups in asub-frame assigned to the parade to which this group belongs, minus 1,e.g., NoG=0 implies that one group is allocated (or assigned) to thisparade in a sub-frame. The value of NoG may range from 0 to 7. Thislimits the amount of data that a parade may take from the main (legacy)service data, and consequently the maximum data that can be carried byone parade. The slot numbers assigned to the corresponding Parade can becalculated from SGN and NoG, using Equation 1. By taking each parade insequence, the specific slots for each parade will be determined, andconsequently the SGN for each succeeding parade. For example, if for aspecific parade SGN=3 and NoG=3 (010b for 3-bit field of NoG),substituting i=3, 4, and 5 in Equation 1 provides slot numbers 12, 2,and 6.

The Parade_repetition_cycle (PRC) field corresponds to the cycle timeover which the parade is transmitted, minus 1, specified in units of MHframes, as described in Table 12.

TABLE 12 PRC Description 000 This parade shall be transmitted once everyMH frame. 001 This parade shall be transmitted once every 2 MH frames.010 This parade shall be transmitted once every 3 MH frames. 011 Thisparade shall be transmitted once every 4 MH frames. 100 This paradeshall be transmitted once every 5 MH frames. 101 This parade shall betransmitted once every 6 MH frames. 110 This parade shall be transmittedonce every 7 MH frames. 111 Reserved

For example, if PRC field value is equal to ‘001’, this indicates thatthe parade shall be transmitted once every 2 MH frame.

The RS_Frame_mode field shall be as defined in Table 1. TheRS_Frame_mode field represents that one parade transmits one RS frame ortwo RS frames.

The RS_code_mode_primary field shall be the RS code mode for the primaryRS frame. Herein, the RS_code_mode_primary field is defined in Table 6.

The RS_code_mode_secondary field shall be the RS code mode for thesecondary RS frame. Herein, the RS_code_mode_secondary field is definedin Table 6.

The SCCC_Block_mode field represents how MH blocks within a data groupare assigned to SCCC block. The SCCC_Block_mode field shall be asdefined in Table 7.

The SCCC_outer_code_mode_A field corresponds to the SCCC outer code modefor Region A within a data group. The SCCC outer code mode is defined inTable 8.

The SCCC_outer_code_mode_B field corresponds to the SCCC outer code modefor Region B within the data group. The SCCC_outer_code_mode_C fieldcorresponds be the SCCC outer code mode for Region C within the datagroup. And, the SCCC_outer_code_mode_D field corresponds to the SCCCouter code mode for Region D within the data group.

The FIC_version field represents a version of FIC data.

The Parade_continuity_counter field counter may increase from 0 to 15and then repeat its cycle. This counter shall increment by 1 every(PRC+1) MH frames. For example, as shown in Table 12, PRC=011 (decimal3) implies that Parade_continuity_counter increases every fourth MHframe.

The TNOG field may be identical for all sub-frames in an MH Frame.

However, the information included in the TPC data presented herein ismerely exemplary. And, since the adding or deleting of informationincluded in the TPC may be easily adjusted and modified by one skilledin the art, the present invention will, therefore, not be limited to theexamples set forth herein.

Since the TPC data (excluding the Sub-Frame_number field and theSlot_number field) for each parade do not change their values during anMH frame, the same information is repeatedly transmitted through all MHgroups belonging to the corresponding parade during an MH frame. Thisallows very robust and reliable reception of the TPC data. Because theSub-Frame_number and the Slot_number are increasing counter values, theyalso are robust due to the transmission of regularly expected values.

Furthermore, the FIC data is provided to enable a fast serviceacquisition of data receivers, and the FIC information includes crosslayer information between the physical layer and the upper layer(s).

FIG. 42 illustrates an example of a transmission scenario of the TPCdata and the FIC data. The values of the Sub-Frame_number field,Slot_number field, Parade_id field, Parade_repetition_cycle field, andParade_continuity_counter field may corresponds to the current MH framethroughout the 5 sub-frames within a specific MH frame. Some of TPCparameters and FIC data are signaled in advance.

The SGN, NoG and all FEC modes may have values corresponding to thecurrent MH frame in the first two sub-frames. The SGN, NoG and all FECmodes may have values corresponding to the frame in which the paradenext appears throughout the 3^(rd), 4^(th) and 5^(th) sub-frames of thecurrent MH frame. This enables the MH receivers to receive (or acquire)the transmission parameters in advance very reliably.

For example, when Parade_repetition_cycle=‘000’, the values of the3^(rd), 4^(th,) and 5^(th) sub-frames of the current MH frame correspondto the next MH frame. Also, when Parade_repetition_cycle=‘011’, thevalues of the 3^(rd), 4^(th), and 5^(th) sub-frames of the current MHframe correspond to the 4^(th) MH frame and beyond.

The FIC_version field and the FIC_data field may have values that applyto the current MH Frame during the 1^(st) sub-frame and the 2^(nd)sub-frame, and they shall have values corresponding to the MH frameimmediately following the current MH frame during the 3^(rd), 4^(th),and 5^(th) sub-frames of the current MH frame.

Meanwhile, the receiving system may turn the power on only during a slotto which the data group of the designated (or desired) parade isassigned, and the receiving system may turn the power off during theremaining slots, thereby reducing power consumption of the receivingsystem. Such characteristic is particularly useful in portable or mobilereceivers, which require low power consumption. For example, it isassumed that data groups of a 1^(st) parade with NOG=3, a 2^(nd) paradewith NOG=2, and a 3^(rd) parade with NOG=3 are assigned to one MH frame,as shown in FIG. 43. It is also assumed that the user has selected amobile service included in the 1^(st) parade using the keypad providedon the remote controller or terminal. In this case, the receiving systemturns the power on only during a slot that data groups of the 1^(st)parade is assigned, as shown in FIG. 43, and turns the power off duringthe remaining slots, thereby reducing power consumption, as describedabove. At this point, the power is required to be turned on brieflyearlier than the slot to which the actual designated data group isassigned (or allocated). This is to enable the tuner or demodulator toconverge in advance.

Assignment of Known Data (or Training Signal)

In addition to the payload data, the MH transmission system inserts longand regularly spaced training sequences into each group. The regularityis an especially useful feature since it provides the greatest possiblebenefit for a given number of training symbols in high-Doppler rateconditions. The length of the training sequences is also chosen to allowfast acquisition of the channel during bursted power-saving operation ofthe demodulator. Each group contains 6 training sequences. The trainingsequences are specified before trellis-encoding. The training sequencesare then trellis-encoded and these trellis-encoded sequences also areknown sequences. This is because the trellis encoder memories areinitialized to pre-determined values at the beginning of each sequence.The form of the 6 training sequences at the byte level (beforetrellis-encoding) is shown in FIG. 44. This is the arrangement of thetraining sequence at the group formatter 303.

The 1^(st) training sequence is located at the last 2 segments of the3^(rd) MH block (B3). The 2^(nd) training sequence may be inserted atthe 2^(nd) and 3^(rd) segments of the 4^(th) MH block (B4). The 2^(nd)training sequence is next to the signaling area, as shown in FIG. 5.Then, the 3^(rd) training sequence, the 4^(th) training sequence, the5^(th) training sequence, and the 6^(th) training sequence may be placedat the last 2 segments of the 4^(th), 5^(th), 6^(th), and 7^(th) MHblocks (B4, B5, B6, and B7), respectively. As shown in FIG. 44, the1^(st) training sequence, the 3^(rd) training sequence, the 4^(th)training sequence, the 5^(th) training sequence, and the 6^(th) trainingsequence are spaced 16 segments apart from one another. Referring toFIG. 44, the dotted area indicates trellis initialization data bytes,the lined area indicates training data bytes, and the white areaincludes other bytes such as the FEC-coded MH service data bytes,FEC-coded signaling data, main service data bytes, RS parity data bytes(for backwards compatibility with legacy ATSC receivers) and/or dummydata bytes.

FIG. 45 illustrates the training sequences (at the symbol level) aftertrellis-encoding by the trellis encoder. Referring to FIG. 45, thedotted area indicates data segment sync symbols, the lined areaindicates training data symbols, and the white area includes othersymbols, such as FEC-coded mobile service data symbols, FEC-codedsignaling data, main service data symbols, RS parity data symbols (forbackwards compatibility with legacy ATSC receivers), dummy data symbols,trellis initialization data symbols, and/or the first part of thetraining sequence data symbols. Due to the intra-segment interleaving ofthe trellis encoder, various types of data symbols will be mixed in thewhite area.

After the trellis-encoding process, the last 1416 (=588+828) symbols ofthe 1^(st) training sequence, the 3^(rd) training sequence, the 4^(th)training sequence, the 5^(th) training sequence, and the 6^(th) trainingsequence commonly share the same data pattern. Including the datasegment synchronization symbols in the middle of and after eachsequence, the total length of each common training pattern is 1424symbols. The 2^(nd) training sequence has a first 528-symbol sequenceand a second 528-symbol sequence that have the same data pattern. Morespecifically, the 528-symbol sequence is repeated after the 4-symboldata segment synchronization signal. At the end of each trainingsequence, the memory contents of the twelve modified trellis encodersshall be set to zero (0).

Receiving System

FIG. 46 is a block diagram illustrating a receiving system according toan embodiment of the present invention.

The receiving system of FIG. 46 includes a tuner 1301, a demodulatingunit 1302, a demultiplexer 1303, a program table buffer 1304, a programtable decoder 1305, a program table storage unit 1306, a data handler1307, a middleware engine 1308, an A/V decoder 1309, an A/Vpost-processor 1310, an application manager 1311, and a user interface1314. The application manager 1311 may include a channel manager 1312and a service manager 1313.

In FIG. 46, solid lines indicate data flows and dotted lines indicatecontrol flows.

The tuner 1301 tunes to a frequency of a specific channel through any ofan antenna, a cable, or a satellite and down-converts the frequency toan Intermediate Frequency (IF) signal and outputs the IF signal to thedemodulating unit 1302. Here, the tuner 1301 is controlled by thechannel manager 1312 in the application manager 1311 and reports theresult and strength of a broadcast signal of the tuned channel to thechannel manager 1312. Data received through the frequency of thespecific channel includes main service data, mobile service data, atransmission parameter, and program table information for decoding themain service data and the mobile service data.

The demodulating unit 1302 performs VSB demodulation, channelequalization, etc., on the signal output from the tuner 1301 andidentifies and separately outputs main service data and mobile servicedata. The demodulating unit 1302 will be described in detail in a later.

On the other hand, the transmitter can transmit signaling information(or TPC information) including transmission parameters by inserting thesignaling information into at least one of a field synchronizationregion, a known data region, and a mobile service data region.Accordingly, the demodulating unit 1302 can extract the transmissionparameters from the field synchronization region, the known data region,and the mobile service data region.

The transmission parameters may include sub-frame information, slotinformation, parade-related information (for example, a parade_id, aparade repeat period, etc.), information of data groups in a sub-frame,RS frame mode information, RS code mode information, SCCC block modeinformation, SCCC outer code mode information, FIC version information,etc.

The demodulating unit 1302 performs block decoding, RS frame decoding,etc., using the extracted transmission parameters. For example, thedemodulating unit 1302 performs block decoding of each region in a datagroup with reference to SCCC-related information (for example, SCCCblock mode information or an SCCC outer code mode) included in thetransmission parameters and performs RS frame decoding of each regionincluded in the data group with reference to RS-related information (forexample, an RS code mode).

In the embodiment of the present invention, an RS frame including mobileservice data demodulated by the demodulating unit 1302 is input to thedemultiplexer 1303.

That is, data inputted to the demultiplexer 1303 has an RS frame dataformat as shown in FIG. 17( a) or FIG. 17( b).

More specifically, the RS frame decoder of the demodulating unit 1302performs the reverse of the encoding process performed at the RS frameencoder of the transmission system to correct errors in the RS frame andthen outputs the error-corrected RS frame to a data derandomizer. Thedata derandomizer then performs derandomizing on the error-corrected RSframe through the reverse of the randomizing process performed at thetransmission system to obtain an RS frame as shown in FIG. 17( a) orFIG. 17( b).

The demultiplexer 1303 may receive RS frames of all parades and may alsoreceive only an RS frame of a parade including a mobile service that theuser desires to receive through power supply control. For example, whenRS frames of all parades are received, the demultiplexer 1303 candemultiplex a parade including a mobile service that the user desires toreceive using a parade_id.

One parade carries one or two RS frames and one ensemble is mapped toone RS frame. Therefore, when one parade carries two RS frames, thedemultiplexer 1303 needs to identify an RS frame carrying an ensembleincluding mobile service data to be decoded from a parade containing amobile service that the user desires to receive. That is, when areceived single parade or a parade demultiplexed from a plurality ofparades carries a primary ensemble and a secondary ensemble, thedemultiplexer 1303 selects one of the primary and secondary ensembles.

In an embodiment, the demultiplexer 1303 can demultiplex an RS framecarrying an ensemble including mobile service data to be decoded usingan ensemble_id created by adding one bit to a left position of theparade_id.

The demultiplexer 1303 refers to the MH header of the MH service datapacket within the RS frame corresponding to the ensemble including themobile service data that are to be decoded, thereby identifying when thecorresponding MH service data packet is the program table information orthe IP datagram of the mobile service data. Alternatively, when theprogram table information and the mobile service data are bothconfigured in the form of IP datagrams, the demultiplexer 1303 may usethe IP address in order to identify the IP datagram of the program tableinformation and the mobile service data.

Herein, the identified program table information is outputted to theprogram table buffer 1304. And, audio/video/data streams are separatedfrom the IP datagram of mobile service data that are to be selectedamong the IP datagrams of the identified mobile service data, therebybeing respectively outputted to the A/V decoder 1309 and/or the datahandler 1307.

According to an embodiment of the present invention, when thestuff_indicator field within the MH header of the MH service data packetindicates that stuffing bytes are inserted in the payload of thecorresponding MH service data packet, the demultiplexer 1303 removes thestuffing bytes from the payload of the corresponding MH service datapacket. Then, the demultiplexer 1303 identifies the program tableinformation and the mobile service data. Thereafter, the demultiplexer1303 identifies A/V/D streams from the identified mobile service data.

The program table buffer 1304 temporarily stores the section-typeprogram table information and then outputs the section-type programtable information to the program table decoder 1305.

The program table decoder 1305 identifies tables using a table_id and asection_length in the program table information and parses sections ofthe identified tables and produces and stores a database of the parsedresults in the program table storage unit 1306. For example, the programtable decoder 1305 collects sections having the same table identifier(table_id) to construct a table. The program table decoder 1305 thenparses the table and produces and stores a database of the parsedresults in the program table storage unit 1306.

The A/V decoder 1309 decodes the audio and video streams outputted fromthe demultiplexer 1303 using audio and video decoding algorithms,respectively. The decoded audio and video data is outputted to the A/Vpost-processor 1310.

Here, at least one of an AC-3 decoding algorithm, an MPEG 2 audiodecoding algorithm, an MPEG 4 audio decoding algorithm, an AAC decodingalgorithm, an AAC+ decoding algorithm, an HE AAC decoding algorithm, anAAC SBR decoding algorithm, an MPEG surround decoding algorithm, and aBSAC decoding algorithm can be used as the audio decoding algorithm andat least one of an MPEG 2 video decoding algorithm, an MPEG 4 videodecoding algorithm, an H.264 decoding algorithm, an SVC decodingalgorithm, and a VC-1 decoding algorithm can be used as the audiodecoding algorithm.

The data handler 8507 processes data stream packets required for databroadcasting among data stream packets separated (or identified) by thedemultiplexer 1303 and provides the processed data stream packets to themiddleware engine 1310 to allow the middleware engine 1310 to bemultiplexed them with A/V data. In an embodiment, the middleware engine1310 is a Java middleware engine.

The application manager 1311 receives a key input from the TV viewer anddisplays a Graphical User Interface (GUI) on the TV screen in responseto a viewer request through a User Interface (UI). The applicationmanager 1311 also writes and reads information regarding overall GUIcontrol of the TV, user requests, and TV system states to and from amemory (for example, NVRAM or flash memory). In addition, theapplication manager 1311 can receive parade-related information (forexample, a parade_id) from the demodulating unit 1302 to control thedemultiplexer 1303 to select an RS frame of a parade including arequired mobile service. The application manager 1311 can also receivean ensemble_id to control the demultiplexer 1303 to select an RS frameof an ensemble including mobile service data to be decoded from theparade. The application manager 1311 also controls the channel manager1312 to perform channel-related operations (for example, channel mapmanagement and program table decoder operations).

The channel manager 1312 manages physical and logical channel maps andcontrols the tuner 1301 and the program table decoder 1305 to respond toa channel-related request of the viewer. The channel manager alsorequests that the program table decoder 1305 parse a channel-relatedtable of a channel to be tuned and receives the parsing results from theprogram table decoder 1305.

Demodulating Unit Within Receiving System

FIG. 47 illustrates an example of a demodulating unit in a digitalbroadcast receiving system according to the present invention. Thedemodulating unit of FIG. 47 uses known data information, which isinserted in the mobile service data section and, then, transmitted bythe transmitting system, so as to perform carrier synchronizationrecovery, frame synchronization recovery, and channel equalization,thereby enhancing the receiving performance. Also the demodulating unitmay turn the power on only during a slot to which the data group of thedesignated (or desired) parade is assigned, thereby reducing powerconsumption of the receiving system.

Referring to FIG. 47, the demodulating unit includes an operationcontroller 2000, a demodulator 2002, an equalizer 2003, a known sequencedetector 2004, a block decoder 2005, and a RS frame decoder 2006. Thedemodulating unit may further include a main service data processor2008. The main service data processor 2008 may include a datadeinterleaver, a RS decoder, and a data derandomizer. The demodulatingunit may further include a signaling decoder 2013. The receiving systemalso may further include a power controller 5000 for controlling powersupply of the demodulating unit.

More specifically, a frequency of a particular channel tuned by a tunerdown converts to an intermediate frequency (IF) signal. Then, thedown-converted data 2001 outputs the down-converted IF signal to thedemodulator 2002 and the known sequence detector 2004. At this point,the down-converted data 2001 is inputted to the demodulator 2002 and theknown sequence detector 2004 via analog/digital converter ADC (notshown). The ADC converts pass-band analog IF signal into pass-banddigital IF signal.

The demodulator 2002 performs self gain control, carrier recovery, andtiming recovery processes on the inputted pass-band digital IF signal,thereby modifying the IF signal to a base-band signal. Then, thedemodulator 2002 outputs the newly created base-band signal to theequalizer 2003 and the known sequence detector 2004.

The equalizer 2003 compensates the distortion of the channel included inthe demodulated signal and then outputs the error-compensated signal tothe block decoder 2005.

At this point, the known sequence detector 2004 detects the knownsequence position information inserted by the transmitting end from theinput/output data of the demodulator 2002 (i.e., the data prior to thedemodulation process or the data after the demodulation process).Thereafter, the position information along with the symbol sequence ofthe known data, which are generated from the detected position, isoutputted to the operation controller 2000, the demodulator 2002, theequalizer 2003, and the signaling decoder 2013. Also, the known sequencedetector 2004 outputs a set of information to the block decoder 2005.This set of information is used to allow the block decoder 2005 of thereceiving system to identify the mobile service data that are processedwith additional encoding from the transmitting system and the mainservice data that are not processed with additional encoding.

In addition, although the connection status is not shown in FIG. 47, theinformation detected from the known sequence detector 2004 may be usedthroughout the entire receiving system and may also be used in the RSframe decoder 2006.

The data demodulated in the demodulator 2002 or the data equalized inthe channel equalizer 2003 is inputted to the signaling decoder 2013.The known data position information detected in the known sequencedetector 2004 is inputted to the signaling decoder 2013.

The signaling decoder 2013 extracts and decodes signaling information(e.g., TPC information), which inserted and transmitted by thetransmitting end, from the inputted data, the decoded signalinginformation provides to blocks requiring the signaling information.

More specifically, the signaling decoder 2013 extracts and decodes TPCdata, which inserted and transmitted by the transmitting end, from theequalized data, and then the decoded TPC data outputs to the operationcontroller 2000, the known sequence detector 2004, and the powercontroller 5000. For example, the TPC data is inserted in a signalinginformation region of each data group, and then is transmitted to areceiving system.

Herein, the TPC data may include RS frame-associated information,SCCC-associated information, MH frame-associated information, and so on,as shown in FIG. 41. The RS frame-associated information may include RSframe mode information and RS code mode information. The SCCC-associatedinformation may include SCCC block mode information and SCCC outer codemode information. The MH frame-associated information may includesub-frame count information, slot count information, parade_idinformation, SGN information, NoG information, and so on.

At this point, the signaling decoder 2013 can know the signalinginformation region within a data group by using the known datainformation being outputted from the known sequence detector 2004.Namely, the 1^(st) known sequence (or training sequence) is located atthe last 2 segments of the 3^(rd) MH block (B3) within the data group.The 2^(nd) training sequence may be inserted at the 2^(nd) and 3^(rd)segments of the 4^(th) MH block (B4). The 2^(nd) known sequence islocated at between 2^(nd) and 3^(rd) segments of the 4^(th) MH block(B4) within the data group. Since the 2^(nd) known sequence is insertedand received next to the signaling information area, the signalingdecoder 2013 may extract and decode signaling information included inthe signaling information region from the data being outputted in thedemodulator 2002 or the channel equalizer 2003.

The power controller 5000 is inputted the MH frame-associatedinformation from the signaling decoder 2013, and controls power of thetuner and the demodulating unit. Alternatively, the power controller5000 is inputted a power control information from the operationcontroller 2000, and controls power of the tuner and the demodulatingunit.

According to the embodiment of the present invention, the powercontroller 5000 turns the power on only during a slot to which a slot ofthe parade including user-selected mobile service is assigned. The powercontroller 5000 then turns the power off during the remaining slots.

For example, it is assumed that data groups of a 1^(st) parade withNOG=3, a 2^(nd) parade with NOG=2, and a 3^(rd) parade with NOG=3 areassigned to one MH frame, as shown in FIG. 43. It is also assumed thatthe user has selected a mobile service included in the 1^(st) paradeusing the keypad provided on the remote controller or terminal. In thiscase, the power controller 5000 turns the power on only during a slotthat data groups of the 1^(st) parade is assigned, as shown in FIG. 43,and turns the power off during the remaining slots, thereby reducingpower consumption.

The demodulator 2002 uses the known data symbol sequence during thetiming and/or carrier recovery, thereby enhancing the demodulatingperformance. Similarly, the equalizer 2003 uses the known data so as toenhance the equalizing performance. Moreover, the decoding result of theblock decoder 2005 may be fed-back to the equalizer 2003, therebyenhancing the equalizing performance.

Demodulator and Known Sequence Detector

At this point, the transmitting system may receive a data frame (or VSBframe) including a data group which known data sequence (or trainingsequence) is periodically inserted therein, as shown in FIG. 5. Herein,the data group is divided into regions A to D, as shown in FIG. 5. Morespecifically, in the example of the present invention, each region A, B,C, and D are further divided into MH blocks B4 to B7, MH blocks B3 andB8, MH blocks B2 and B9, MH blocks B1 and B10, respectively.

Referring to FIG. 44 and FIG. 45, known data sequence having the samepattern are included in each known data section that is beingperiodically inserted. Herein, the length of the known data sequencehaving identical data patterns may be either equal to or different fromthe length of the entire (or total) known data sequence of thecorresponding known data section (or block). If the two lengths aredifferent from one another, the length of the entire known data sequenceshould be longer than the length of the known data sequence havingidentical data patterns. In this case, the same known data sequences areincluded in the entire known data sequence.

Accordingly, when the known data sequence is periodically inserted inmobile service data as described above, the channel equalizer includedin the receiving system used the inserted known data as a trainingsequence, so as to be used either for an accurate decision value or forestimating a channel impulse response.

Meanwhile, when known data sequence having the same pattern isperiodically inserted, each known data sequence may be used as a guardinterval in a channel equalizer according to the present invention.Herein, the guard interval prevents interference that occurs betweenblocks due to a multiple path channel. This is because the known datasequence located behind a mobile service data section (i.e., data block)may be considered as being copied in front of the mobile service datasection.

The above-described structure is referred to as a cyclic prefix. Thisstructure provides circular convolution in a time domain between a datablock transmitted from the transmitting system and a channel impulseresponse. Accordingly, this facilitates the channel equalizer of thereceiving system to perform channel equalization in a frequency domainby using a fast fourier transform (FFT) and an inverse fast fouriertransform (IFFT).

More specifically, when viewed in the frequency domain, the data blockreceived by the receiving system is expressed as a multiplication of thedata block and the channel impulse response. Therefore, when performingthe channel equalization, by multiplying the inverse of the channel inthe frequency domain, the channel equalization may be performed moreeasily.

The known sequence detector 2004 detects the position of the known databeing periodically inserted and transmitted as described above. At thesame time, the known sequence detector 2004 may also estimate initialfrequency offset during the process of detecting known data. In thiscase, the demodulator 2002 may estimate with more accuracy carrierfrequency offset from the information on the known data positioninformation and initial frequency offset estimation value, therebycompensating the estimated carrier frequency offset.

Meanwhile, when known data is transmitted, as shown in FIG. 5, the knownsequence detector 2004 detects a position of second known data region byusing known data of the second known data region that the same patternis repeated twice.

At this point, since the known sequence detector 2004 is well-informedof the data group structure, when the position of the second known dataregion is detected, the known sequence detector 2004 can estimatepositions of the first, third, fourth, fifth, and sixth known dataregions of a corresponding data group by counting symbols or segmentsbased upon the second known data region position. If the correspondingdata group is a data group including field synchronization segment, theknown sequence detector 2004 can estimate the position of the fieldsynchronization segment of the corresponding data group, which ispositioned chronologically before the second known data region, bycounting symbols or segments based upon the second known data regionposition. Also, the known sequence detector 2004 may estimate the knowndata position information and the field synchronization positioninformation from the parade including mobile service selected by a userbased on the MH frame-associated information outputted from thesignaling decoder 2013.

At least one of the estimated known data poison information and fieldsynchronization information is provided to the demodulator 2002, thechannel equalizer 2003, the signaling decoder 2013, and the operationcontroller 2000.

Also, the known sequence detector 2004 may estimate initial frequencyoffset by using known data inserted in the second known data region(i.e., ACQ known data region). In this case, the demodulator 2002 mayestimate with more accuracy carrier frequency offset from theinformation on the known data position information and initial frequencyoffset estimation value, thereby compensating the estimated carrierfrequency offset.

Channel Equalizer

The demodulated data using the known data in the demodulator 2002 isinputted to the channel equalizer 2003. The demodulated data is inputtedto the known sequence detector 2004.

The equalizer 2003 may perform channel equalization by using a pluralityof methods. An example of estimating a channel impulse response (CIR) soas to perform channel equalization will be given in the description ofthe present invention.

Most particularly, an example of estimating the CIR in accordance witheach region within the data group, which is hierarchically divided andtransmitted from the transmitting system, and applying each CIRdifferently will also be described herein. Furthermore, by using theknown data, the place and contents of which is known in accordance withan agreement between the transmitting system and the receiving system,and/or the field synchronization data, so as to estimate the CIR, thepresent invention may be able to perform channel equalization with morestability.

Herein, the data group that is inputted for the equalization process isdivided into regions A to D, as shown in FIG. 5. More specifically, inthe example of the present invention, each region A, B, C, and D arefurther divided into MH blocks B4 to B7, MH blocks B3 and B8, MH blocksB2 and B9, MH blocks B1 and B10, respectively.

More specifically, a data group can be assigned and transmitted amaximum the number of 4 in a VSB frame in the transmitting system. Inthis case, all data group do not include field synchronization data. Inthe present invention, the data group including the fieldsynchronization data performs channel-equalization using the fieldsynchronization data and known data. And the data group not includingthe field synchronization data performs channel-equalization using theknown data. For example, the data of the MH block B3 including the fieldsynchronization data performs channel-equalization using the CIRcalculated from the field synchronization data area and the CIRcalculated from the first known data area. Also, the data of the MHblocks B1 and B2 performs channel-equalization using the CIR calculatedfrom the field synchronization data area and the CIR calculated from thefirst known data area. Meanwhile, the data of the MH blocks B1 to B3 notincluding the field synchronization data performs channel-equalizationusing CIRS calculated from the first known data area and the third knowndata area.

As described above, the present invention uses the CIR estimated fromthe field synchronization data and the known data sequences in order toperform channel equalization on data within the data group. At thispoint, each of the estimated CIRs may be directly used in accordancewith the characteristics of each region within the data group.Alternatively, a plurality of the estimated CIRs may also be eitherinterpolated or extrapolated so as to create a new CIR, which is thenused for the channel equalization process.

Herein, when a value F(Q) of a function F(x) at a particular point Q anda value F(S) of the function F(x) at another particular point S areknown, interpolation refers to estimating a function value of a pointwithin the section between points Q and S. Linear interpolationcorresponds to the simplest form among a wide range of interpolationoperations. The linear interpolation described herein is merelyexemplary among a wide range of possible interpolation methods. And,therefore, the present invention is not limited only to the examples setforth herein.

Alternatively, when a value F(Q) of a function F(x) at a particularpoint Q and a value F(S) of the function F(x) at another particularpoint S are known, extrapolation refers to estimating a function valueof a point outside of the section between points Q and S. Linearextrapolation is the simplest form among a wide range of extrapolationoperations. Similarly, the linear extrapolation described herein ismerely exemplary among a wide range of possible extrapolation methods.And, therefore, the present invention is not limited only to theexamples set forth herein.

Operation Controller

The operation controller 2000 receives the known data positioninformation and the transmission parameter information and then forwardsMH frame time information, a presence or non-presence of a data group ofa selected parade, position information of known data within the datagroup, power control information and the like to each block of thedemodulating unit. The operation controller 2000, as shown in FIG. 47,controls operations of the demodulator 2002, the channel equalizer 2003,the block decoder 2005 and the RS frame decoder 2006. And, the operationcontroller 2000 is able to overall operations of the demodulating unit(not shown in the drawing). Moreover, the operation controller 2000 canbe implemented with the separate block or can be included within aprescribed one of the blocks of the demodulating unit shown in FIG. 47.

FIG. 48 is an overall block diagram of an operation controller 2000.

Referring to FIG. 48, the operation controller 2000 can include a paradeID checker 3101, a frame synchronizer 3102, a parade mapper 3103, agroup controller 3104 and a known sequence indication controller 3105.

The operation controller 2000 receives known data position informationfrom the known sequence detector 2004 and receives transmissionparameter information from the signaling decoder 2013. The operationcontroller 2000 then generates a control signal necessary for ademodulating unit of a receiving system. For instance, the known dataposition information detected by the known sequence detector 2004 isinputted to the known sequence indication controller 3105. And, thetransmission parameter information (i.e., TPC data) decoded by thesignaling decoder 2013 is inputted to the parade ID checker 3101.

The parade ID checker 3101 compares a parade ID (parade ID selected by auser) contained in the user control signal to a parade ID inputted fromthe signaling decoder 2013. If the two parade IDs are not identical toeach other, the parade ID checker stands by until a next transmissionparameter is inputted from the signaling decoder 2013.

If the two parade IDs are identical to each other, the parade ID checker3101 outputs the transmission parameter information to the blocks withinthe operation controller 2000 and the overall system.

If it is checked that the parade ID in the transmission parameterinformation inputted to the parade ID checker 3101 is identical to theparade ID selected by a user, the parade ID checker 3101 outputsstarting_group_number (SGN) and number_of_groups (NOG) to the parademapper 3103, outputs sub_frame_number, slot_number andparade_repetition_cycle PRC) to the frame synchronizer 3102, outputsSCCC_block_mode, SCCC_outer_code_mode_A, SCCC_outer_code_mode_B,SCCC_outer_code_mode_C and SCCC_outer_code_mode_D to the block decoder2005, and outputs RS_frame_mode, RS_code_mode_primary andRs_code_mode_secondary to the RS frame decoder 2006.

The parade mapper 3103 receives the SGN and the NOG from the parade IDchecker as inputs, decides a data group is carried by which one ofsixteen slots within a Sub-frame, and then outputs the correspondinginformation. Data group number transmitted every sub-frame is set to aninteger consecutive between SGN and (SGN+NOG−1). For instance, if SGN=3and NOG=4, four groups, of which group numbers are 3, 4, 5 and 6, aretransmitted for the corresponding sub-frames, respectively. The parademapper finds a slot number j for transmitting a data group according toEquation 1 with a group number i obtained from SGN and NOG.

In the above example, in case of SGN=3 and NOG=4, if they are insertedin Equation 1, slot numbers of groups transmitted according to the aboveformula sequentially become 12, 2, 6 and 10.

The parade mapper 3103 then outputs the found slot number information.

For example of outputting slot numbers, a method of using a bit vectorhaving 16 bits is available.

A bit vector SNi (i=0˜15) can be set to 1 if there exists a grouptransmitted for an i^(th) slot. A bit vector SNi (i=0˜15) can be set to0 if a group transmitted for an i^(th) slot does not exist. And, thisbit vector can be outputted as slot number information.

The frame synchronizer 3102 receives the sub_frame_number, slot-numberand PRC from the parade ID checker and then sends slot_counter andframe_mask signals as outputs. The slot_counter is the signal indicatinga slot_number at a current timing point at which a receiver isoperating. And, the frame_mask is the signal indicating whether acorresponding parade is transmitted for a current frame. The framesynchronizer 3102 performs a process for initializing slot_counter,sub_frame_number and frame_counter in receiving signaling informationinitially. A counter value of a current timing point is generated fromadding a delayed slot number L according to a time taken to decodesignaling from demodulation together with the signaling informationinputted in this process. After completion of the initializationprocess, slot_counter is updated every single slot period, updatessub_frame_counter every period of the slot_counter value, and updatesframe_counter every period of the sub_frame_counter. By referring to theframe_counter information and the PRC information, a frame_mask signalis generated. For example, if a corresponding parade is beingtransmitted for a current frame, ‘1’ is outputted as the frame_mask.Otherwise, it is able to output ‘0’.

The group controller 3104 receives the slot number information from theparade mapper 3103. The group controller 3104 receives the slot_counterand frame_mask information from the frame synchronizer 3102. The groupcontroller 3104 then outputs group_presence_indicator indicating whetheran MH group is being transmitted. For instance, if the slot numberinformation inputted from the parade mapper 3103 corresponds to 12, 2, 6and 10, when the frame_mask information inputted from the framesynchronizer 3102 is 1 and the slot_counter inputted from the framesynchronizer 3102 includes 2, 6, 10 and 12, ‘1’ is outputted as thegroup_presence_indicator. Otherwise, it is able to output 0.

The known sequence indication controller 3105 outputs positioninformation of another known data, group start position information andthe like with position information of specific inputted known data. Inthis case, since the known data are present at a previously appointedposition within the data group, if position data of one of a pluralityof known data sequences, it is able to know data position information ofanother known sequence, data group start position information and thelike. The known sequence indication controller 3105 can output knowndata and data group position information necessary for the demodulatingunit of the receiving system using the group_presence_indicatorinformation only if the data group is transmitted. Alternatively, theknown sequence detector 2004 can perform operations of the knownsequence indication controller 3105.

Block Decoder

Meanwhile, if the data being inputted to the block decoder 2005, afterbeing channel-equalized by the equalizer 2003, correspond to the datahaving both block encoding and trellis encoding performed thereon (i.e.,the data within the RS frame, the signaling information data, etc.) bythe transmitting system, trellis decoding and block decoding processesare performed on the inputted data as inverse processes of thetransmitting system. Alternatively, if the data being inputted to theblock decoder 2005 correspond to the data having only trellis encodingperformed thereon (i.e., the main service data), and not the blockencoding, only the trellis decoding process is performed on the inputteddata as the inverse process of the transmitting system.

The trellis decoded and block decoded data by the block decoder 2005 arethen outputted to the RS frame decoder 2006. More specifically, theblock decoder 2005 removes the known data, data used for trellisinitialization, and signaling information data, MPEG header, which havebeen inserted in the data group, and the RS parity data, which have beenadded by the RS encoder/non-systematic RS encoder or non-systematic RSencoder of the transmitting system. Then, the block decoder 2005 outputsthe processed data to the RS frame decoder 2006. Herein, the removal ofthe data may be performed before the block decoding process, or may beperformed during or after the block decoding process.

Meanwhile, the data trellis-decoded by the block decoder 2005 areoutputted to the data deinterleaver of the main service data processor2008. At this point, the data being trellis-decoded by the block decoder2005 and outputted to the data deinterleaver may not only include themain service data but may also include the data within the RS frame andthe signaling information. Furthermore, the RS parity data that areadded by the transmitting system after the pre-processor 230 may also beincluded in the data being outputted to the data deinterleaver.

According to another embodiment of the present invention, data that arenot processed with block decoding and only processed with trellisencoding by the transmitting system may directly bypass the blockdecoder 2005 so as to be outputted to the data deinterleaver. In thiscase, a trellis decoder should be provided before the datadeinterleaver. More specifically, if the inputted data correspond to thedata having only trellis encoding performed thereon and not blockencoding, the block decoder 2005 performs Viterbi (or trellis) decodingon the inputted data so as to output a hard decision value or to performa hard-decision on a soft decision value, thereby outputting the result.

Meanwhile, if the inputted data correspond to the data having both blockencoding process and trellis encoding process performed thereon, theblock decoder 2005 outputs a soft decision value with respect to theinputted data.

In other words, if the inputted data correspond to data being processedwith block encoding by the block processor 302 and being processed withtrellis encoding by the trellis encoding module 256, in the transmittingsystem, the block decoder 2005 performs a decoding process and a trellisdecoding process on the inputted data as inverse processes of thetransmitting system. At this point, the RS frame encoder of thepre-processor included in the transmitting system may be viewed as anouter (or external) encoder. And, the trellis encoder may be viewed asan inner (or internal) encoder. When decoding such concatenated codes,in order to allow the block decoder 2005 to maximize its performance ofdecoding externally encoded data, the decoder of the internal codeshould output a soft decision value.

FIG. 49 illustrates a detailed block diagram of the block decoder 2005according to an embodiment of the present invention. Referring to FIG.49, the block decoder 2005 includes a feedback controller 4010, an inputbuffer 4011, a trellis decoding unit (or 12-way trellis coded modulation(TCM) decoder or inner decoder) 4012, a symbol-byte converter 4013, anouter block extractor 4014, a feedback deformatter 4015, a symboldeinterleaver 4016, an outer symbol mapper 4017, a symbol decoder 4018,an inner symbol mapper 4019, a symbol interleaver 4020, a feedbackformatter 4021, and an output buffer 4022. Herein, just as in thetransmitting system, the trellis decoding unit 4012 may be viewed as aninner (or internal) decoder. And, the symbol decoder 4018 may be viewedas an outer (or external) decoder.

The input buffer 4011 temporarily stores the mobile service data symbolsbeing channel-equalized and outputted from the equalizer 2003. (Herein,the mobile service data symbols may include symbols corresponding to thesignaling information, RS parity data symbols and CRC data symbols addedduring the encoding process of the RS frame.) Thereafter, the inputbuffer 4011 repeatedly outputs the stored symbols for M number of timesto the trellis decoding unit 4012 in a turbo block (TDL) size requiredfor the turbo decoding process.

The turbo decoding length (TDL) may also be referred to as a turboblock. Herein, a TDL should include at least one SCCC block size.Therefore, as defined in FIG. 5, when it is assumed that one MH block isa 16-segment unit, and that a combination of 10 MH blocks form one SCCCblock, a TDL should be equal to or larger than the maximum possiblecombination size. For example, when it is assumed that 2 MH blocks formone SCCC block, the TDL may be equal to or larger than 32 segments(i.e., 828×32=26496 symbols). Herein, M indicates a number ofrepetitions for turbo-decoding pre-decided by the feed-back controller4010.

Also, M represents a number of repetitions of the turbo decodingprocess, the number being predetermined by the feedback controller 4010.

Additionally, among the values of symbols being channel-equalized andoutputted from the equalizer 2003, the input symbol values correspondingto a section having no mobile service data symbols (including RS paritydata symbols during RS frame encoding and CRC data symbols) includedtherein, bypass the input buffer 4011 without being stored. Morespecifically, since trellis-encoding is performed on input symbol valuesof a section wherein SCCC block-encoding has not been performed, theinput buffer 4011 inputs the inputted symbol values of the correspondingsection directly to the trellis encoding module 4012 without performingany storage, repetition, and output processes. The storage, repetition,and output processes of the input buffer 4011 are controlled by thefeedback controller 4010. Herein, the feedback controller 4010 refers toSCCC-associated information (e.g., SCCC block mode and SCCC outer codemode), which are outputted from the signaling decoder 2013 or theoperation controller 2000, in order to control the storage and outputprocesses of the input buffer 4011.

The trellis decoding unit 4012 includes a 12-way TCM decoder. Herein,the trellis decoding unit 4012 performs 12-way trellis decoding asinverse processes of the 12-way trellis encoder.

More specifically, the trellis decoding unit 4012 receives a number ofoutput symbols of the input buffer 4011 and soft-decision values of thefeedback formatter 4021 equivalent to each TDL, so as to perform the TCMdecoding process.

At this point, based upon the control of the feedback controller 4010,the soft-decision values outputted from the feedback formatter 4021 arematched with a number of mobile service data symbol places so as to bein a one-to-one (1:1) correspondence. Herein, the number of mobileservice data symbol places is equivalent to the TDL being outputted fromthe input buffer 4011.

More specifically, the mobile service data being outputted from theinput buffer 4011 are matched with the turbo decoded data beinginputted, so that each respective data place can correspond with oneanother. Thereafter, the matched data are outputted to the trellisdecoding unit 4012. For example, if the turbo decoded data correspond tothe third symbol within the turbo block, the corresponding symbol (ordata) is matched with the third symbol included in the turbo block,which is outputted from the input buffer 4011. Subsequently, the matchedsymbol (or data) is outputted to the trellis decoding unit 4012.

In order to do so, while the regressive turbo decoding is in process,the feedback controller 4010 controls the input buffer 4011 so that theinput buffer 4011 stores the corresponding turbo block data. Also, bydelaying data (or symbols), the soft decision value (e.g., LLR) of thesymbol outputted from the symbol interleaver 4020 and the symbol of theinput buffer 4011 corresponding to the same place (or position) withinthe block of the output symbol are matched with one another to be in aone-to-one correspondence. Thereafter, the matched symbols arecontrolled so that they can be inputted to the TCM decoder through therespective path. This process is repeated for a predetermined number ofturbo decoding cycle periods. Then, the data of the next turbo block areoutputted from the input buffer 4011, thereby repeating the turbodecoding process.

The output of the trellis decoding unit 4012 signifies a degree ofreliability of the transmission bits configuring each symbol. Forexample, in the transmitting system, since the input data of the trellisencoding module correspond to two bits as one symbol, a log likelihoodratio (LLR) between the likelihood of a bit having the value of ‘1’ andthe likelihood of the bit having the value of ‘0’ may be respectivelyoutputted (in bit units) to the upper bit and the lower bit. Herein, thelog likelihood ratio corresponds to a log value for the ratio betweenthe likelihood of a bit having the value of ‘1’ and the likelihood ofthe bit having the value of ‘0’. Alternatively, a LLR for the likelihoodof 2 bits (i.e., one symbol) being equal to “00”, “01”, “10”, and “11”may be respectively outputted (in symbol units) to all 4 combinations ofbits (i.e., 00, 01, 10, 11). Consequently, this becomes the softdecision value that indicates the degree of reliability of thetransmission bits configuring each symbol. A maximum a posterioriprobability (MAP) or a soft-out Viterbi algorithm (SOVA) may be used asa decoding algorithm of each TCM decoder within the trellis decodingunit 4012.

The output of the trellis decoding unit 4012 is inputted to thesymbol-byte converter 4013 and the outer block extractor 4014.

The symbol-byte converter 4013 performs a hard-decision process of thesoft decision value that is trellis decoded and outputted from thetrellis decoding unit 4012. Thereafter, the symbol-byte converter 4013groups 4 symbols into byte units, which are then outputted to the datadeinterleaver of the main service data processor 2008 of FIG. 47. Morespecifically, the symbol-byte converter 4013 performs hard-decision inbit units on the soft decision value of the symbol outputted from thetrellis decoding unit 4012. Therefore, the data processed withhard-decision and outputted in bit units from the symbol-byte converter4013 not only include main service data, but may also include mobileservice data, known data, RS parity data, and MPEG headers.

Among the soft decision values of TDL size of the trellis decoding unit4012, the outer block extractor 4014 identifies the soft decision valuesof B size of corresponding to the mobile service data symbols (whereinsymbols corresponding to signaling information, RS parity data symbolsthat are added during the encoding of the RS frame, and CRC data symbolsare included) and outputs the identified soft decision values to thefeedback deformatter 4015.

The feedback deformatter 4015 changes the processing order of the softdecision values corresponding to the mobile service data symbols. Thisis an inverse process of an initial change in the processing order ofthe mobile service data symbols, which are generated during anintermediate step, wherein the output symbols outputted from the blockprocessor 302 of the transmitting system are being inputted to thetrellis encoding module 256 (e.g., when the symbols pass through thegroup formatter, the data deinterleaver, the packet formatter, and thedata interleaver). Thereafter, the feedback deformatter 2015 performsreordering of the process order of soft decision values corresponding tothe mobile service data symbols and, then, outputs the processed mobileservice data symbols to the symbol deinterleaver 4016.

This is because a plurality of blocks exist between the block processor302 and the trellis encoding module 256, and because, due to theseblocks, the order of the mobile service data symbols being outputtedfrom the block processor 302 and the order of the mobile service datasymbols being inputted to the trellis encoding module 256 are notidentical to one another. Therefore, the feedback deformatter 4015reorders (or rearranges) the order of the mobile service data symbolsbeing outputted from the outer block extractor 4014, so that the orderof the mobile service data symbols being inputted to the symboldeinterleaver 4016 matches the order of the mobile service data symbolsoutputted from the block processor 302 of the transmitting system. Thereordering process may be embodied as one of software, middleware, andhardware.

The symbol deinterleaver 4016 performs deinterleaving on the mobileservice data symbols having their processing orders changed andoutputted from the feedback deformatter 4015, as an inverse process ofthe symbol interleaving process of the symbol interleaver 514 includedin the transmitting system. The size of the block used by the symboldeinterleaver 4016 during the deinterleaving process is identical tointerleaving size of an actual symbol (i.e., B) of the symbolinterleaver 514, which is included in the transmitting system. This isbecause the turbo decoding process is performed between the trellisdecoding unit 4012 and the symbol decoder 4018. Both the input andoutput of the symbol deinterleaver 4016 correspond to soft decisionvalues, and the deinterleaved soft decision values are outputted to theouter symbol mapper 4017.

The operations of the outer symbol mapper 4017 may vary depending uponthe structure and coding rate of the convolution encoder 513 included inthe transmitting system. For example, when data are ½-rate encoded bythe convolution encoder 513 and then transmitted, the outer symbolmapper 4017 directly outputs the input data without modification. Inanother example, when data are ¼-rate encoded by the convolution encoder513 and then transmitted, the outer symbol mapper 4017 converts theinput data so that it can match the input data format of the symboldecoder 4018. For this, the outer symbol mapper 4017 may be inputtedSCCC-associated information (i.e., SCCC block mode and SCCC outer codemode) from the signaling decoder 2013. Then, the outer symbol mapper4017 outputs the converted data to the symbol decoder 4018.

The symbol decoder 4018 (i.e., the outer decoder) receives the dataoutputted from the outer symbol mapper 4017 and performs symbol decodingas an inverse process of the convolution encoder 513 included in thetransmitting system. At this point, two different soft decision valuesare outputted from the symbol decoder 4018. One of the outputted softdecision values corresponds to a soft decision value matching the outputsymbol of the convolution encoder 513 (hereinafter referred to as a“first decision value”). The other one of the outputted soft decisionvalues corresponds to a soft decision value matching the input bit ofthe convolution encoder 513 (hereinafter referred to as a “seconddecision value”).

More specifically, the first decision value represents a degree ofreliability the output symbol (i.e., 2 bits) of the convolution encoder513. Herein, the first soft decision value may output (in bit units) aLLR between the likelihood of 1 bit being equal to ‘1’ and thelikelihood of 1 bit being equal to ‘0’ with respect to each of the upperbit and lower bit, which configures a symbol. Alternatively, the firstsoft decision value may also output (in symbol units) a LLR for thelikelihood of 2 bits being equal to “00”, “01”, “10”, and “11” withrespect to all possible combinations. The first soft decision value isfed-back to the trellis decoding unit 4012 through the inner symbolmapper 4019, the symbol interleaver 4020, and the feedback formatter4021. On the other hand, the second soft decision value indicates adegree of reliability the input bit of the convolution encoder 513included in the transmitting system. Herein, the second soft decisionvalue is represented as the LLR between the likelihood of 1 bit beingequal to ‘1’ and the likelihood of 1 bit being equal to ‘0’. Thereafter,the second soft decision value is outputted to the outer buffer 4022. Inthis case, a maximum a posteriori probability (MAP) or a soft-outViterbi algorithm (SOVA) may be used as the decoding algorithm of thesymbol decoder 4018.

The first soft decision value that is outputted from the symbol decoder4018 is inputted to the inner symbol mapper 4019. The inner symbolmapper 4019 converts the first soft decision value to a data formatcorresponding the input data of the trellis decoding unit 4012.Thereafter, the inner symbol mapper 4019 outputs the converted softdecision value to the symbol interleaver 4020. The operations of theinner symbol mapper 4019 may also vary depending upon the structure andcoding rate of the convolution encoder 513 included in the transmittingsystem.

The symbol interleaver 4020 performs symbol interleaving, as shown inFIG. 36, on the first soft decision value that is outputted from theinner symbol mapper 4019. Then, the symbol interleaver 4020 outputs thesymbol-interleaved first soft decision value to the feedback formatter4021. Herein, the output of the symbol interleaver 4020 also correspondsto a soft decision value.

With respect to the changed processing order of the soft decision valuescorresponding to the symbols that are generated during an intermediatestep, wherein the output symbols outputted from the block processor 302of the transmitting system are being inputted to the trellis encodingmodule (e.g., when the symbols pass through the group formatter, thedata deinterleaver, the packet formatter, the RS encoder, and the datainterleaver), the feedback formatter 4021 alters (or changes) the orderof the output values outputted from the symbol interleaver 4020.Subsequently, the feedback formatter 4020 outputs values to the trellisdecoding unit 4012 in the changed order. The reordering process of thefeedback formatter 4021 may configure at least one of software,hardware, and middleware.

The soft decision values outputted from the symbol interleaver 4020 arematched with the positions of mobile service data symbols each havingthe size of TDL, which are outputted from the input buffer 4011, so asto be in a one-to-one correspondence. Thereafter, the soft decisionvalues matched with the respective symbol position are inputted to thetrellis decoding unit 4012. At this point, since the main service datasymbols or the RS parity data symbols and known data symbols of the mainservice data do not correspond to the mobile service data symbols, thefeedback formatter 4021 inserts null data in the correspondingpositions, thereby outputting the processed data to the trellis decodingunit 4012. Additionally, each time the symbols having the size of TDLare turbo decoded, no value is fed-back by the symbol interleaver 4020starting from the beginning of the first decoding process. Therefore,the feedback formatter 4021 is controlled by the feedback controller4010, thereby inserting null data into all symbol positions including amobile service data symbol. Then, the processed data are outputted tothe trellis decoding unit 4012.

The output buffer 4022 receives the second soft decision value from thesymbol decoder 4018 based upon the control of the feedback controller4010. Then, the output buffer 4022 temporarily stores the receivedsecond soft decision value. Thereafter, the output buffer 4022 outputsthe second soft decision value to the RS frame decoder 2006. Forexample, the output buffer 4022 overwrites the second soft decisionvalue of the symbol decoder 4018 until the turbo decoding process isperformed for M number of times. Then, once all M number of turbodecoding processes is performed for a single TDL, the correspondingsecond soft decision value is outputted to the RS frame decoder 2006.

The feedback controller 4010 controls the number of turbo decoding andturbo decoding repetition processes of the overall block decoder, shownin FIG. 49. More specifically, once the turbo decoding process has beenrepeated for a predetermined number of times, the second soft decisionvalue of the symbol decoder 4018 is outputted to the RS frame decoder2006 through the output buffer 4022. Thus, the block decoding process ofa turbo block is completed. In the description of the present invention,this process is referred to as a regressive turbo decoding process forsimplicity.

At this point, the number of regressive turbo decoding rounds betweenthe trellis decoding unit 4012 and the symbol decoder 4018 may bedefined while taking into account hardware complexity and errorcorrection performance. Accordingly, if the number of rounds increases,the error correction performance may be enhanced. However, this may leadto a disadvantageous of the hardware becoming more complicated (orcomplex).

Meanwhile, the main service data processor 2008 corresponds to blockrequired for receiving the main service data. Therefore, theabove-mentioned blocks may not be necessary (or required) in thestructure of a digital broadcast receiving system for receiving mobileservice data only.

The data deinterleaver of the main service data processor 2008 performsan inverse process of the data interleaver included in the transmittingsystem. In other words, the data deinterleaver deinterleaves the mainservice data outputted from the block decoder 2005 and outputs thedeinterleaved main service data to the RS decoder. The data beinginputted to the data deinterleaver include main service data, as well asmobile service data, known data, RS parity data, and an MPEG header. Atthis point, among the inputted data, only the main service data and theRS parity data added to the main service data packet may be outputted tothe RS decoder. Also, all data outputted after the data derandomizer mayall be removed with the exception for the main service data. In theembodiment of the present invention, only the main service data and theRS parity data added to the main service data packet are inputted to theRS decoder.

The RS decoder performs a systematic RS decoding process on thedeinterleaved data and outputs the processed data to the dataderandomizer.

The data derandomizer receives the output of the RS decoder andgenerates a pseudo random data byte identical to that of the randomizerincluded in the digital broadcast transmitting system. Thereafter, thedata derandomizer performs a bitwise exclusive OR (XOR) operation on thegenerated pseudo random data byte, thereby inserting the MPEGsynchronization bytes to the beginning of each packet so as to outputthe data in 188-byte main service data packet units.

RS Frame Decoder

The data outputted from the block decoder 2005 are in portion units.More specifically, in the transmitting system, the RS frame is dividedinto several portions, and the mobile service data of each portion areassigned either to regions A/B/C/D within the data group or to any oneof regions A/B and regions C/D , thereby being transmitted to thereceiving system. Therefore, the RS frame decoder 2006 groups severalportions included in a parade so as to form an RS frame. Alternatively,the RS frame decoder 2006 may also group several portions included in aparade so as to form two RS frames. Thereafter, error correctiondecoding is performed in RS frame units.

For example, when the RS frame mode value is equal to ‘00’, then oneparade transmits one RS frame. At this point, one RS frame is dividedinto several portions, and the mobile service data of each portion areassigned to regions A/B/C/D of the corresponding data group, therebybeing transmitted. In this case, the RS frame decoder 2006 extractsmobile service data from regions A/B/C/D of the corresponding datagroup, as shown in FIG. 50( a). Subsequently, the RS frame decoder 2006may perform the process of forming (or creating) a portion on aplurality of data group within a parade, thereby forming severalportions. Then, the several portions of mobile service data may begrouped to form an RS frame. Herein, if stuffing bytes are added to thelast portion, the RS frame may be formed after removing the stuffingbyte.

In another example, when the RS frame mode value is equal to ‘01’, thenone parade transmits two RS frames (i.e., a primary RS frame and asecondary RS frame). At this point, a primary RS frame is divided intoseveral primary portions, and the mobile service data of each primaryportion are assigned to regions A/B of the corresponding data group,thereby being transmitted. Also, a secondary RS frame is divided intoseveral secondary portions, and the mobile service data of eachsecondary portion are assigned to regions C/D of the corresponding datagroup, thereby being transmitted.

In this case, the RS frame decoder 2006 extracts mobile service datafrom regions A/B of the corresponding data group, as shown in FIG. 50(b). Subsequently, the RS frame decoder 2006 may perform the process offorming (or creating) a primary portion on a plurality of data groupwithin a parade, thereby forming several primary portions. Then, theseveral primary portions of mobile service data may be grouped to form aprimary RS frame. Herein, if stuffing bytes are added to the lastprimary portion, the primary RS frame may be formed after removing thestuffing byte. Also, the RS frame decoder 2006 extracts mobile servicedata from regions C/D of the corresponding data group. Subsequently, theRS frame decoder 2006 may perform the process of forming (or creating) asecondary portion on a plurality of data group within a parade, therebyforming several secondary portions. Then, the several secondary portionsof mobile service data may be grouped to form a secondary RS frame.Herein, if stuffing bytes are added to the last secondary portion, thesecondary RS frame may be formed after removing the stuffing byte.

More specifically, the RS frame decoder 2006 receives the RS-encodedand/or CRC-encoded mobile service data of each portion from the blockdecoder 2005. Then, the RS frame decoder 2006 groups several portions,which are inputted based upon RS frame-associated information outputtedfrom the signaling decoder 2013 or the operation controller 2000,thereby performing error correction. By referring to the RS frame modevalue included in the RS frame-associated information, the RS framedecoder 2006 may form an RS frame and may also be informed of the numberof RS code parity data bytes and the code size. Herein, the RS code isused to configure (or form) the RS frame. The RS frame decoder 2006 alsorefers to the RS frame-associated information in order to perform aninverse process of the RS frame encoder, which is included in thetransmitting system, thereby correcting the errors within the RS frame.Thereafter, the RS frame decoder 2006 adds 1 MPEG synchronization databyte to the error-correction mobile service data packet. In an earlierprocess, the 1 MPEG synchronization data byte was removed from themobile service data packet during the RS frame encoding process.Finally, the RS frame decoder 2006 performs a derandomizing process onthe processed mobile service data packet.

FIG. 51 illustrates, when the RS frame mode value is equal to ‘00’, anexemplary process of grouping several portion being transmitted to aparade, thereby forming an RS frame and an RS frame reliability map, andan exemplary process of performing a row de-permutation process in superframe units as an inverse process of the transmitting system, therebyre-distinguishing (or identifying) the row-de-permuted RS frame and RSframe reliability map. More specifically, the RS frame decoder 2006receives and groups a plurality of mobile service data bytes, so as toform an RS frame. According to the present invention, in transmittingsystem, the mobile service data correspond to data RS-encoded in RSframe units and also correspond to data row-permuted in super frameunits. At this point, the mobile service data may already be errorcorrection encoded (e.g., CRC-encoded). Alternatively, the errorcorrection encoding process may be omitted.

It is assumed that, in the transmitting system, an RS frame having thesize of (N+2)×(187+P) bytes is divided into M number of portions, andthat the M number of mobile service data portions are assigned andtransmitted to regions A/B/C/D in M number of data groups, respectively.In this case, in the receiving system, each mobile service data portionis grouped, as shown in FIG. 51( a), thereby forming an RS frame havingthe size of (N+2)×(187+P) bytes. At this point, when stuffing bytes (S)are added to at least one portion included in the corresponding RS frameand then transmitted, the stuffing bytes are removed, therebyconfiguring an RS frame and an RS frame reliability map. For example, asshown in FIG. 33, when S number of stuffing bytes are added to thecorresponding portion, the S number of stuffing bytes are removed,thereby configuring the RS frame and the RS frame reliability map.

Herein, when it is assumed that the block decoder 2005 outputs a softdecision value for the decoding result, the RS frame decoder 2006 maydecide the ‘0’ and ‘1’ of the corresponding bit by using the codes ofthe soft decision value. 8 bits that are each decided as described aboveare grouped to create 1 data byte. If the above-described process isperformed on all soft decision values of several portions (or datagroups) included in a parade, the RS frame having the size of(N+2)×(187+P) bytes may be configured.

Additionally, the present invention uses the soft decision value notonly to configure the RS frame but also to configure a reliability map.

Herein, the reliability map indicates the reliability of thecorresponding data byte, which is configured by grouping 8 bits, the 8bits being decided by the codes of the soft decision value.

For example, when the absolute value of the soft decision value exceedsa pre-determined threshold value, the value of the corresponding bit,which is decided by the code of the corresponding soft decision value,is determined to be reliable. Conversely, when the absolute value of thesoft decision value does not exceed the pre-determined threshold value,the value of the corresponding bit is determined to be unreliable.Thereafter, if even a single bit among the 8 bits, which are decided bythe codes of the soft decision value and group to configure one databyte, is determined to be unreliable, the corresponding data byte ismarked on the reliability map as an unreliable data byte.

Herein, determining the reliability of one data byte is only exemplary.More specifically, when a plurality of data bytes (e.g., at least 4 databytes) are determined to be unreliable, the corresponding data bytes mayalso be marked as unreliable data bytes within the reliability map.Conversely, when all of the data bits within the one data byte aredetermined to be reliable (i.e., when the absolute value of the softdecision values of all 8 bits included in the one data byte exceed thepredetermined threshold value), the corresponding data byte is marked tobe a reliable data byte on the reliability map. Similarly, when aplurality of data bytes (e.g., at least 4 data bytes) are determined tobe reliable, the corresponding data bytes may also be marked as reliabledata bytes within the reliability map. The numbers proposed in theabove-described example are merely exemplary and, therefore, do notlimit the scope or spirit of the present invention.

The process of configuring the RS frame and the process of configuringthe reliability map both using the soft decision value may be performedat the same time. Herein, the reliability information within thereliability map is in a one-to-one correspondence with each byte withinthe RS frame. For example, if a RS frame has the size of (N+2)×(187+P)bytes, the reliability map is also configured to have the size of(N+2)×(187+P) bytes. FIG. 51( a′) and FIG. 51( b′) respectivelyillustrate the process steps of configuring the reliability mapaccording to the present invention.

At this point, the RS frame of FIG. 51( b) and the RS frame reliabilitymap of FIG. 51( b′) are interleaved in super frame units. Therefore, theRS frame and the RS frame reliability maps are grouped to create a superframe and a super frame reliability map. Subsequently, as shown in FIG.51( c) and FIG. 51( c′), a de-permutation (or deinterleaving) process isperformed in super frame units on the RS frame and the RS framereliability maps, as an inverse process of the transmitting system.Then, when the de-permutation process is performed in super frame units,the processed data are divided into de-permuted (or deinterleaved) RSframes having the size of (N+2)×(187+P) bytes and de-permuted RS framereliability maps having the size of (N+2)×(187+P) bytes, as shown inFIG. 51( d) and FIG. 51( d′). Subsequently, the RS frame reliability mapis used on the divided RS frames so as to perform error correction.

FIG. 52 illustrates example of the error correction processed accordingto embodiments of the present invention. FIG. 52 illustrates an exampleof performing an error correction process when the transmitting systemhas performed both RS encoding and CRC encoding processes on the RSframe.

As shown in FIG. 52( a) and FIG. 52( a′), when the RS frame having thesize of (N+2)×(187+P) bytes and the RS frame reliability map having thesize of (N+2)×(187+P) bytes are created, a CRC syndrome checking processis performed on the created RS frame, thereby verifying whether anyerror has occurred in each row. Subsequently, as shown in FIG. 52( b), a2-byte checksum is removed to configure an RS frame having the size ofN×(187+P) bytes. Herein, the presence (or existence) of an error isindicated on an error flag corresponding to each row. Similarly, sincethe portion of the reliability map corresponding to the CRC checksum hashardly any applicability, this portion is removed so that only N×(187+P)number of the reliability information bytes remain, as shown in FIG. 52(b′).

After performing the CRC syndrome checking process, as described above,a RS decoding process is performed in a column direction. Herein, a RSerasure correction process may be performed in accordance with thenumber of CRC error flags. More specifically, as shown in FIG. 52( c),the CRC error flag corresponding to each row within the RS frame isverified. Thereafter, the RS frame decoder 2006 determines whether thenumber of rows having a CRC error occurring therein is equal to orsmaller than the maximum number of errors on which the RS erasurecorrection may be performed, when performing the RS decoding process ina column direction. The maximum number of errors corresponds to P numberof parity bytes inserted when performing the RS encoding process. In theembodiment of the present invention, it is assumed that 48 parity byteshave been added to each column (i.e., P=48).

If the number of rows having the CRC errors occurring therein is smallerthan or equal to the maximum number of errors (i.e., 48 errors accordingto this embodiment) that can be corrected by the RS erasure decodingprocess, a (235,187)-RS erasure decoding process is performed in acolumn direction on the RS frame having (187+P) number of N-byte rows(i.e., 235 N-byte rows), as shown in FIG. 52(d). Thereafter, as shown inFIG. 52( e), the 48-byte parity data that have been added at the end ofeach column are removed. Conversely, however, if the number of rowshaving the CRC errors occurring therein is greater than the maximumnumber of errors (i.e., 48 errors) that can be corrected by the RSerasure decoding process, the RS erasure decoding process cannot beperformed. In this case, the error may be corrected by performing ageneral RS decoding process. In addition, the reliability map, which hasbeen created based upon the soft decision value along with the RS frame,may be used to further enhance the error correction ability (orperformance) of the present invention.

More specifically, the RS frame decoder 2006 compares the absolute valueof the soft decision value of the block decoder 2005 with thepre-determined threshold value, so as to determine the reliability ofthe bit value decided by the code of the corresponding soft decisionvalue. Also, 8 bits, each being determined by the code of the softdecision value, are grouped to form one data byte. Accordingly, thereliability information on this one data byte is indicated on thereliability map. Therefore, as shown in FIG. 52( c), even though aparticular row is determined to have an error occurring therein basedupon a CRC syndrome checking process on the particular row, the presentinvention does not assume that all bytes included in the row have errorsoccurring therein. The present invention refers to the reliabilityinformation of the reliability map and sets only the bytes that havebeen determined to be unreliable as erroneous bytes. In other words,with disregard to whether or not a CRC error exists within thecorresponding row, only the bytes that are determined to be unreliablebased upon the reliability map are set as erasure points.

According to another method, when it is determined that CRC errors areincluded in the corresponding row, based upon the result of the CRCsyndrome checking result, only the bytes that are determined by thereliability map to be unreliable are set as errors. More specifically,only the bytes corresponding to the row that is determined to haveerrors included therein and being determined to be unreliable based uponthe reliability information, are set as the erasure points. Thereafter,if the number of error points for each column is smaller than or equalto the maximum number of errors (i.e., 48 errors) that can be correctedby the RS erasure decoding process, an RS erasure decoding process isperformed on the corresponding column. Conversely, if the number oferror points for each column is greater than the maximum number oferrors (i.e., 48 errors) that can be corrected by the RS erasuredecoding process, a general decoding process is performed on thecorresponding column.

More specifically, if the number of rows having CRC errors includedtherein is greater than the maximum number of errors (i.e., 48 errors)that can be corrected by the RS erasure decoding process, either an RSerasure decoding process or a general RS decoding process is performedon a column that is decided based upon the reliability information ofthe reliability map, in accordance with the number of erasure pointswithin the corresponding column. For example, it is assumed that thenumber of rows having CRC errors included therein within the RS frame isgreater than 48. And, it is also assumed that the number of erasurepoints decided based upon the reliability information of the reliabilitymap is indicated as 40 erasure points in the first column and as 50erasure points in the second column. In this case, a (235,187)-RSerasure decoding process is performed on the first column.Alternatively, a (235,187)-RS decoding process is performed on thesecond column. When error correction decoding is performed on all columndirections within the RS frame by using the above-described process, the48-byte parity data which were added at the end of each column areremoved, as shown in FIG. 52( e).

As described above, even though the total number of CRC errorscorresponding to each row within the RS frame is greater than themaximum number of errors that can be corrected by the RS erasuredecoding process, when the number of bytes determined to have a lowreliability level, based upon the reliability information on thereliability map within a particular column, while performing errorcorrection decoding on the particular column. Herein, the differencebetween the general RS decoding process and the RS erasure decodingprocess is the number of errors that can be corrected. Morespecifically, when performing the general RS decoding process, thenumber of errors corresponding to half of the number of parity bytes(i.e., (number of parity bytes)/2) that are inserted during the RSencoding process may be error corrected (e.g., 24 errors may becorrected). Alternatively, when performing the RS erasure decodingprocess, the number of errors corresponding to the number of paritybytes that are inserted during the RS encoding process may be errorcorrected (e.g., 48 errors may be corrected).

After performing the error correction decoding process, as describedabove, a RS frame configured of 187 N-byte rows (or packet) may beobtained as shown in FIG. 52( e). The RS frame having the size of N×187bytes is outputted by the order of N number of 187-byte units. At thispoint, 1 MPEG synchronization byte, which had been removed by thetransmitting system, is added to each 187-byte packet, as shown in FIG.52( f). Therefore, a 188-byte unit mobile service data packet isoutputted.

At this point, the RS frame decoded mobile service data is performed aderandomizing process, which corresponds to the inverse process of therandomizer included in the transmitting system and then the derandomizeddata are outputted, thereby obtaining the mobile service datatransmitted from the transmitting system. In the present invention, theRS frame decoder 2006 may perform the data derandomizing function.

An RS frame decoder may be configured of M number of RS frame decodersprovided in parallel, wherein the number of RS frame encoders is equalto the number of parades (=M) within an MH frame, a multiplexer formultiplexing each portion and being provided to each input end of the Mnumber of RS frame decoders, and a demultiplexer for demultiplexing eachportion and being provided to each output end of the M number of RSframe decoders.

As described above, the present invention has the following advantages.Herein, the present invention is robust (or strong) against any errorthat may occur when transmitting mobile broadcast service data through achannel. And, the present invention is also highly compatible to theconventional system.

Moreover, the service multiplexer packetizes the RS frame for mobileservice into a plurality of MPEG-2 TS packets, which are thentransmitted to each transmitter. Thereafter, each transmitter groups aplurality of MPEG-2 TS packets so as to recover an RS frame, therebyusing the conventional interface standard between the servicemultiplexer and the transmitter without modification.

Additionally, the present invention may also receive the mobilebroadcast service data without any error occurring, even in channelshaving severe ghost effect and noise.

Furthermore, by inserting known data in a specific position within adata region and by transmitting the processed data, the receivingperformance of a receiving system may be enhanced even in channelenvironments (or conditions) undergoing frequent channel changes.

The present invention is even more effective when applied to mobile andportable receivers, which are also liable to frequent change inchannels, and which require strength (or robustness) against intensenoise.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A transmitting system, comprising: a service multiplexer forgenerating a Reed-Solomon (RS) frame having the size ofN(row)×187(column) bytes including at least one type of mobile servicedata, packetizing the RS frame into a plurality of mobile service datapackets, and multiplexing the packetized mobile service data packetswith a main service data packet at a predetermined data rate, therebytransmitting the multiplexed data packets, wherein each mobile servicedata packet is configured of a TS header and a data region, and whereinthe data region is configured of at least one of a payload region and anadaptation field region; and at least one transmitter for being locatedin a remote position from the service multiplexer, recovering the RSframe from the plurality of mobile service data packets based upon theTS header of each mobile service data packet transmitted from theservice multiplexer, and performing error correction encoding and blockencoding on data of the recovered RS frame, thereby transmitting theprocessed RS frame data to a receiving system.
 2. The transmittingsystem of claim 1, wherein the service multiplexer sets, among theplurality of mobile service data packets, a payload unit start indicator(PUSI) field value of the TS header included in the mobile service datapacket including the first data byte of the RS frame data to ‘1’, andwherein the service multiplexer sets the PUSI field value of the TSheader included in each of the remaining mobile service data packets to‘0’.
 3. The transmitting system of claim 2, wherein the servicemultiplexer sets an ensemble identifier corresponding to the RS frame asa packet identifier (PID) of the TS header included in each of theplurality of mobile service data packets.
 4. The transmitting system ofclaim 1, wherein a number of mobile service data packets beingpacketized from the RS frame is decided by applying the equation below:number of mobile service data packets=└(N×187)/184┘+1, wherein └X┘represents a maximum integer not larger than X, and N indicates a numberof columns in the corresponding RS frame.
 5. The transmitting system ofclaim 4, wherein, when the size of the RS frame corresponds to amultiple of 184 bytes, the service multiplexer configures └(N×187)/184┘number of mobile service data packets by dividing the RS frame data into184-byte units, each including a 4-byte TS header and a payload regionincluding data of each of the divided 184 bytes, and wherein the servicemultiplexer configures a └(N×187)/184┘+1^(th) mobile service data packetincluding a 4-byte TS header and a 184-byte adaptation field regionincluding stuffing data.
 6. The transmitting system of claim 4, wherein,when the size of the RS frame does not correspond to a multiple of 184bytes, the service multiplexer configures └(N×187)/184┘ number of mobileservice data packets by dividing the RS frame data into 184-byte units,each including a 4-byte TS header and a payload region including data ofeach of the divided 184 bytes, and wherein the service multiplexerconfigures a └(N×187)/184┘+1^(th) mobile service data packet including a4-byte TS header, a (184-N4)-byte adaptation field region includingstuffing data (wherein N4 represents a number of non-packetized databytes among the RS frame data), and a payload region including N4 bytesof non-packetized data bytes among the RS frame data.
 7. Thetransmitting system of claim 1, wherein the data rate predetermined bythe service multiplexer corresponds to 19.39 Mbps.
 8. The transmittingsystem of claim 7, wherein, when the output data rate of the multiplexedmobile service data packet and the main service data packet is smallerthan 19.39 Mbps, the service multiplexer generates at least one nulldata packet so as to adjust the output data rate to 19.39 Mbps.
 9. Thetransmitting system of claim 3, wherein the transmitter extracts dataincluded in the payload region of each mobile service data packet havingan ensemble identifier corresponding to the RS frame, which is to berecovered, as a respective packet identifier (PID) value, therebyrecovering the RS frame.
 10. The transmitting system of claim 9, whereinthe transmitter selects a first mobile service data packet of the RSframe based upon a PUSI field value of the TS header included in thereceived mobile service data packet, and wherein the transmitter selectsa last mobile service data packet of the RS frame based upon anadaptation field control field value of the TS header.
 11. In a methodfor processing data in a transmitting system including a servicemultiplexer and at least one transmitter located in a remote positionfrom the service multiplexer, the method comprising: generating aReed-Solomon (RS) frame having the size of N(row)×187(column) bytesincluding at least one type of mobile service data; packetizing the RSframe into a plurality of mobile service data packets, wherein eachmobile service data packet is configured of a TS header and a dataregion, and wherein the data region is configured of at least one of apayload region and an adaptation field region; and multiplexing thepacketized mobile service data packets with a main service data packetat a predetermined data rate, thereby transmitting the multiplexed datapackets to each transmitter.
 12. The transmitting system of claim 11,wherein, among the plurality of mobile service data packets, a payloadunit start indicator (PUSI) field value of the TS header included in themobile service data packet including the first data byte of the RS framedata is set to ‘1’, and wherein the PUSI field value of the TS headerincluded in each of the remaining mobile service data packets is set to‘0’.
 13. The method of claim 11, wherein an ensemble identifiercorresponding to the RS frame is set as a packet identifier (PID) of theTS header included in each of the plurality of mobile service datapackets.
 14. The method of claim 11, wherein a number of mobile servicedata packets being packetized from the RS frame is decided by applyingthe equation below: number of mobile service datapackets=└(N×187)/184┘+1, wherein └X┘ represents a maximum integer notlarger than X, and N indicates a number of columns in the correspondingRS frame.
 15. The method of claim 14, wherein, when the size of the RSframe corresponds to a multiple of 184 bytes, └(N×187)/184┘ number ofmobile service data packets are configured by dividing the RS frame datainto 184-byte units, each including a 4-byte TS header and a payloadregion including data of each of the divided 184 bytes, and wherein a└(N×187)/184┘+1^(th) mobile service data packet is configured to includea 4-byte TS header and a 184-byte adaptation field region includingstuffing data.
 16. The method of claim 14, wherein, when the size of theRS frame does not correspond to a multiple of 184 bytes, └(N×187)/184┘number of mobile service data packets are configured by dividing the RSframe data into 184-byte units, each including a 4-byte TS header and apayload region including data of each of the divided 184 bytes, andwherein a └(N×187)/184┘+1^(th) mobile service data packet is configuredto include a 4-byte TS header, a (184-N4)-byte adaptation field regionincluding stuffing data (wherein N4 represents a number ofnon-packetized data bytes among the RS frame data), and a payload regionincluding N4 bytes of non-packetized data bytes among the RS frame data.17. The method of claim 11, wherein the predetermined data ratecorresponds to 19.39 Mbps.
 18. The method of claim 17, when the outputdata rate of the multiplexed mobile service data packet and the mainservice data packet is smaller than 19.39 Mbps, further comprisinggenerating at least one null data packet so as to adjust the output datarate to 19.39 Mbps.
 19. The method of claim 11, further comprising:recovering the RS frame from the plurality of mobile service datapackets based upon the TS header of each mobile service data packettransmitted from the service multiplexer; and performing errorcorrection encoding and block encoding on data of the recovered RSframe, thereby transmitting the processed RS frame data to a receivingsystem.
 20. The method of claim 19, wherein data included in a payloadregion of each mobile service data packet having an ensemble identifiercorresponding to the RS frame, which is to be recovered, are extractedas a respective packet identifier (PID) value, thereby recovering the RSframe.